Violence is pervasive in modern society and appears to be escalating. Entirely apart from repression, wars and terrorist activities, the media daily report in banner headlines on the mayhem inflicted by humans upon each other in “civilized” as well as more primitive communities. Whether there has been a real increase or this simply represents more thorough reporting is arguable. After all, violence has been a feature of human interaction since prehistoric ages. Nevertheless, violence has become one of the leading causes of death in modern industrial societies—in some segments of the community it is the leading cause of death—and it is increasingly being recognized as a public health problem.

Inescapably, it finds its way into the workplace. From 1980 to 1989, homicide was the third leading cause of death from injury in North American workplaces, according to data compiled by the National Traumatic Occupational Facilities Surveillance System (NIOSH 1993a). During this period, occupational homicides accounted for 12% of deaths from injury in the workplace; only motor vehicles and machines accounted for more. By 1993, that figure had risen to 17%, a rate of 0.9 per 100,000 workers, now second only to motor vehicle deaths (Toscano and Windau 1994). For  women  workers,  it  remained  the  leading  cause  of  work-related death, although the rate (0.4 deaths per 100,000) was lower than that for men (1.2 deaths per 100,000) (Jenkins 1995).

These deaths, however, represent only the “tip of the iceberg”. For example, in 1992, about 22,400 American workers were injured seriously enough in non-fatal assaults in the workplace to require days away from work to recuperate (Toscano and Windau 1994). Reliable and complete data are lacking, but it is estimated that for every death there have been many thousands—perhaps, even hundreds of thousands—of instances of violence in the workplace.

In its newsletter, Unison, the large British union of health care and governmental service workers, has labelled violence as “the most threatening risk faced by members at work. It is the risk which is most likely to lead to injury. It can bring unmanageable levels of occupational stress which damages personal esteem and threatens people’s ability to continue on the job” (Unison 1992).

This article will summarize the characteristics of violence in the workplace, the kinds of people involved, its effects on them and their employers, and the steps that may be taken to prevent or control such effects.

Definition of Violence

There is no consensus on the definition of violence. For example, Rosenberg and Mercy (1991) include in the definition both fatal and nonfatal interpersonal violence where physical force or other means is used by one person with the intent of causing harm, injury or death to another. The Panel on the Understanding and Control of Violent Behavior convened by the US National Academy of Sciences adopted the definition of violence as: behaviours by individuals that intentionally threaten, attempt or inflict physical harm on others (Reiss and Roth 1993).

These definitions focus on threatening or causing physical harm. However, they exclude instances in which verbal abuse, harassment or humiliation and other forms of psychological trauma may be the sole harm to the victim and which may be no less devastating. They also exclude sexual harassment, which may be physical but which is usually entirely non-physical. In the national survey of American workers conducted by the Northwestern National Life Insurance Company, the researchers separated violent acts into: harassment (the act of creating a hostile environment through unwelcome words, actions or physical contacts not resulting in physical harm), threats (expressions of an intent to cause physical harm), and physical attacks (aggression resulting in a physical assault with or without the use of a weapon) (Lawless, 1993).

In the UK, the Health and Safety Executive’s working definition of workplace violence is: any incident in which an employee is abused, threatened or assaulted by a member of the public in circumstances arising out of the course of his or her employment. Assailants may be patients, clients or co-workers (MSF 1993).

In this article, the term violence will be used in its broadest sense to include all forms of aggressive or abusive behaviour that may cause physical or psychological harm or discomfort to its victims, whether they be intentional targets or innocent bystanders involved only impersonally or incidentally. While workplaces may be targets of terrorist attacks or may become involved in riots and mob violence, such instances will not be discussed.

Prevalence of Violence in the Workplace

Accurate information on the prevalence of violence in the workplace is lacking. Most of the literature focuses on cases that are formally reported: homicides which get tallied in the obligatory death registries, cases that get enmeshed in the criminal justice system, or cases involving time off the job that generate workers’ compensation claims. Yet, for every one of these, there is an untold number of instances in which workers are victims of aggressive, abusive behaviour. For example, according to a survey conducted by the Bureau of Justice Statistics in the US Department of Justice, over half the victimizations sustained at work were not reported to the police. About 40% of the respondents said they did not report the incident because they considered it to be a minor or a personal matter, while another 27% said they did report it to a manager or a company security officer but, apparently, the report was not relayed to the police (Bachman 1994). In addition to the lack of a consensus on a taxonomy of violence, other reasons for under-reporting include:

• Cultural acceptance of violence. There is in many communities a widespread tolerance for violence among or against certain groups (Rosenberg and Mercy 1991). Although frowned upon by many, violence is often rationalized and tolerated as a “normal” response to competition. Violence among minority and ethnic groups is often condoned as a righteous response to discrimination, poverty and lack of access to social or economic equity resulting in low self-esteem and low valuations of human life. As a result, the assault is seen as a consequence of living in a violent society rather than working in an unsafe workplace. Finally, there is the “on-the-job syndrome”, in which workers in certain jobs are expected to put up with verbal abuse, threats and, even, physical attacks (SEIU 1995; Unison 1992).
• Lack of a reporting system. Only a small proportion of organizations have articulated an explicit policy on violence or have designed procedures for reporting and investigating instances of alleged violence in the workplace. Even where such a system has been installed, the trouble of obtaining, completing and filing the required report form is a deterrent to reporting all but the most outrageous incidents.
• Fear of blame or reprisal. Workers may fear being held responsible when they have been attacked by a client or a patient. Fear of reprisal by the assailant is also a potent deterrent to reporting, especially when that person is the worker’s superior and in a position to affect his or her job status.
• Lack of interest on the part of the employer. The employer’s lack of interest in investigating and reacting to prior incidents will certainly discourage reporting. Also, supervisors, concerned that workplace violence might reflect unfavourably on their managerial capabilities may actually discourage or even block the filing of reports by workers in their units.

To determine the prevalence of violence in the workplace in the absence of reliable data, attempts have been made to extrapolate both from available statistics (e.g., death certificates, crime reports and workers’ compensation systems) and from specially designed surveys. Thus, the US National Crime Victimization Survey estimated that about 1 million American workers (out of a workforce of 110 million) are assaulted at work each year (Bachman 1994). And, a 1993 telephone survey of a national sample of 600 American full-time workers (excluding self-employed and military personnel) found that one in four said that he or she had been a victim of workplace violence during the study year: 19%ere harassed, 7% were threatened, and 3% were attacked physically. The researchers reported further that 68%of the harassment victims, 43% of the threat victims and 24% of the attack victims had not reported the incident (Lawless 1993).

A similar survey of workers in the UK employed by the National Health Service revealed that, during the previous year, 0.5% had required medical treatment following an on-the-job physical assault; 11% had suffered a minor injury requiring only first aid, 4 to 6% had been threatened by persons wielding a deadly weapon, and 17% had received verbal threats. Violence was a special problem for emergency staff in ambulances and accident departments, nurses, and workers involved in the care of psychologically disturbed patients (Health Services Advisory Committee 1987). The risk of health workers being confronted by violence has been labelled a feature of everyday work in primary care and in accident/emergency departments (Shepherd 1994).

Homicide in the Workplace

Although workplace homicides are only a small proportion of all homicides, their substantial contribution to work-related deaths, at least in the United States, their unique features, and the possibility of preventive interventions by employers earn them special attention. For example, while most homicides in the community involve people who know each other, many of them close relatives, and only 13% were reported to have been associated with another felony, these proportions were reversed in the workplace, where more than three-fourths of the homicides were committed in the course of a robbery (NIOSH 1992). Further, while persons aged 65 and older in the general population have the lowest rates of being victims of homicide, this age group has the highest rates of such involvement in workplace homicides (Castillo and Jenkins 1994).

American workplaces with the highest rates of homicide are listed in table 1. Over 50% are accounted for by only two industries: retail trade and services. The latter includes taxi driving, which has nearly 40 times the average workplace homicide rate, followed by liquor/convenience stores and gas stations, prime targets for robberies, and by detective/protective services (Castillo and Jenkins 1994).

Table 1. US workplaces with the highest rates of occupational homicide, 1980-1989

¹ Number per 100,000 workers per year.

Source: NIOSH 1993b.

Table 2 lists the occupations with the highest rates of workplace homicides. Again, reflecting the likelihood of involvement in attempted felonies, taxi drivers head the list, followed by law-enforcement personnel, hotel clerks and workers in various types of retail establishments. Commenting on similar data from the UK, Drever (1995) noted that most of the occupations with the highest mortality from homicides had high rates of drug dependence (scaffolders, literary and artistic occupations, painters and decorators) or alcohol abuse (cooks and kitchen porters, publicans, bartenders and caterers).

Table 2. US occupations with the highest rates of occupational homicide, 1980-1989

¹ Number per 100,000 workers per year.

Source: NIOSH 1993b.

As noted above, the vast majority of work-related homicides occur during the course of a robbery or other crime committed by a person or persons usually not known to the victim. Risk factors associated with such incidents are listed in table 3.

Table 3. Risk factors for workplace homicides

Working alone or in small numbers

Exchange of money with the public

Working late night or early morning hours

Working in high crime areas

Guarding valuable property or possessions

Working in community settings (e.g. taxi drivers and police)

Source: NIOSH 1993b.

About 4% of workplace homicides occur during confrontations with family members or acquaintances who have followed the victim into the workplace. About 21% arise out of a confrontation related to the workplace: about two-thirds of these are perpetrated by workers or former employees with a grudge against a manager or a co-worker, while angry customers or clients account for the rest (Toscano and Windau 1994). In these cases, the target may be the particular manager or worker whose actions provoked the assault or, where there is a grudge against the organization, the target may be the workplace itself, and any employees and visitors who just happen to be in it at the critical moment. Sometimes, the assailant may be emotionally disturbed, as in the case of Joseph T. Weisbecker, an employee on long-term disability leave from his employer in Louisville, Kentucky, because of mental illness, who killed eight co-workers and injured 12 others before taking his own life (Kuzmits 1990).

Causes of Violence

Current understanding of the causes and risk factors for assaultive violence is very rudimentary (Rosenberg and Mercy 1991). Clearly, it is a multifactorial problem in which each incident is shaped by the characteristics of the assailant, the characteristics of the victim(s) and the nature of the interplay between them. Reflecting such complexity, a number of theories of causation have been developed. Biological theories, for example, focus on such factors as gender (most of the assailants are male), age (involvement in violence in the community diminishes with age but, as noted above, this is not so in the workplace), and the influence of hormones such as testosterone, neurotransmitters such as serotonin, and other such biological agents. The psychological approach focuses on personality, holding that violence is engendered by deprivation of love during childhood, and childhood abuse, and is learned from role models, reinforced by rewards and punishments in early life. Sociological theories emphasize as breeders of violence such cultural and subcultural factors as poverty, discrimination and lack of economic and social equity. Finally, interactional theories converge on a sequence of actions and reactions that ultimately escalate into violence (Rosenberg and Mercy 1991).

A number of risk factors have been associated with violence. They include:

Mental illness

The vast majority of people who are violent are not mentally ill, and the vast proportion of individuals with mental illness are not violent (American Psychiatric Association 1994). However, mentally disordered individuals are sometimes frightened, irritable, suspicious, excitable, or angry, or a combination of these (Bullard 1994). The resultant behaviour poses a particular risk of violence to the physicians, nurses and staff members involved in their care in ambulances, emergency departments and both inpatient and outpatient psychiatric facilities.

Certain types of mental illness are associated with a greater propensity for violence. Persons with psychopathic personalities tend to have a low threshold for anger and frustration, which often generate violent behaviour (Marks 1992), while individuals with paranoia are suspicious and prone to attack individuals or entire organizations whom they blame when things do not go as they would wish. However, violence may be exhibited by persons with other forms of mental illness. Furthermore, some mentally ill individuals are prone to episodes of acute dementia in which they may inflict violence on themselves as well as on those trying to restrain them.

Alcohol and drug abuse

Alcohol abuse has a strong association with aggressive and violent behaviour. While drunkenness on the part of either assailants or victims, or both, often results in violence, there is disagreement as to whether alcohol is the cause of the violence or merely one of a number of factors involved in its causation (Pernanen 1993). Fagan (1993) emphasized that while alcohol affects neurobiological functions, perception and cognition, it is the immediate setting in which the drinking takes place that channels the disinhibiting responses to alcohol. This was confirmed by a study in Los Angeles County which found that violent incidents were much more frequent in some bars and relatively uncommon in others where just as much drinking was taking place, and concluded that violent behaviour was not related to the amount of alcohol being consumed but, rather, to the kinds of individuals attracted to a particular drinking establishment and the kinds of unwritten rules in effect there (Scribner, MacKinnon and Dwyer 1995).

Much the same may be said for abuse of illicit drugs. Except perhaps for crack cocaine and the amphetamines, drug use is more likely to be associated with sedation and withdrawal rather than aggressive, violent behaviour. Most of the violence associated with illegal drugs seems to be associated not with the drugs, but with the effort to obtain them or the wherewithal to purchase them, and from involvement in the illegal drug traffic.

Violence in the community

Violence in the community not only spills over into workplaces but is a particular risk factor for workers such as police and firefighters,  and  for  postal  workers  and  other  government employees, repair and service personnel, social workers and others whose jobs take them into neighbourhoods in which violence and crime are indigenous. Important factors in the frequency of violence, particularly in the United States, is the prevalence of firearms in the hands of the general public and, especially for young people, the amount of violence depicted in films and on television.

Work-Related Factors Associated with Violence

Instances of violence may occur in any and all workplaces. There are, however, certain jobs and work-related circumstances that are particularly associated with a risk of generating or being subjected to violence. They include:

Criminal activities

Perhaps the least complex of episodes of work-related violence are those associated with criminal violence, the major cause of worksite homicides. These fall into two categories: those involved with attempts at robbery or other felonies, and those related to traffic in illicit drugs. Police, security guards and other personnel with law-enforcement responsibilities face a constant risk of attack by felons attempting to enter the workplace and those resisting detection and arrest. Those working alone and field workers whose duties take them into high-crime neighbourhoods are frequent targets of robbery attempts. Health professionals making home visits to such areas are particularly at risk because they often carry drugs and drug paraphernalia such as hypodermic syringes and needles.

Dealing with the public

Workers in government and private community service agencies, banks and other institutions serving the public are frequently confronted by attacks from individuals who have been kept waiting unduly, have been greeted with disinterest and indifference (whether real or perceived), or were thwarted in obtaining the information or services they desired because of complicated bureaucratic procedures or technicalities that made them ineligible. Clerks in retail establishments receiving items being returned, workers staffing airport ticket counters when flights are overbooked, delayed or cancelled, urban bus or trolley drivers and conductors, and others who must deal with customers or clients whose wants cannot immediately be satisfied are often targets for verbal and sometimes even physical abuse. Then, there are also those who must contend with impatient and unruly crowds, such as police officers, security guards, ticket takers and ushers at popular sporting and entertainment events.

Violent attacks on government workers, particularly those in uniform, and on government buildings and offices in which workers and visitors may be indiscriminately injured or killed, may result from resentment and anger at laws and official policies which the perpetrators will not accept.

Work stress

High levels of work stress may precipitate violent behaviour, while violence in the workplace can, in turn, be a potent stressor. The elements of work stress are well known (see chapter Psychosocial and Organizational Factors). Their common denominator is a devaluation of the individual and/or the work he or she performs, resulting in fatigue, frustration and anger directed at managers and co-workers perceived to be inconsiderate, unfair and abusive. Several recent population studies have demonstrated an association  between  violence  and  job  loss,  one  of  the  most  potent job-related stressors (Catalano et al. 1993; Yancey et al. 1994).

Interpersonal environment in the workplace

The interpersonal environment in the workplace may be a breeding ground for violence. Discrimination and harassment, forms of violence in themselves as defined in this article, may provoke violent retaliation. For example, MSF, the British union of workers in management, science and finance, calls attention to workplace bullying (defined as persistent offensive, abusive, intimidating, malicious or insulting behaviour, abuse of power or unfair penal sanctions), as a characteristic of the management style in some organizations (MSF 1995).

Sexual harassment has been branded a form of assault on the job (SEIU 1995). It may involve unwelcome touching or patting, physical assault, suggestive remarks or other verbal abuse, staring or leering, requests for sexual favours, compromising invitations, or a work environment made offensive by pornography. It is illegal in the United States, having been declared a form of sexual discrimination under Title VII of the Civil Rights Act of 1964 when the worker feels that his or her job status depends on tolerating the advances or if the harassment creates an intimidating, hostile or offensive workplace environment.

Although women are the usual targets, men have also been sexually harassed, albeit much less frequently. In a 1980 survey of US federal employees, 42% of female respondents and 15% of males said that they had been sexually harassed on the job, and a follow-up survey in 1987 yielded similar results (SEIU 1995). In the United States, extensive media coverage of the harassment of women who had “intruded” into jobs and workplaces traditionally filled by males, and the notoriety given to the involvement of prominent political and public figures in alleged harassment, have resulted in an increase in the number of complaints received by state and federal anti-discrimination agencies and the number of civil law suits filed.

Working in health care and social services

In addition to the attempted robberies as noted above, health care staff are often targets of violence from anxious and disturbed patients, especially in emergency and outpatient departments, where long waits and impersonal procedures are not uncommon and where anxiety and anger may boil over into verbal or physical assaults. They may also be victims of assault by family members or friends of patients who had unfavourable outcomes which they rightly or wrongfully attribute to denials, delays or errors in treatment. In such instances they may attack the particular health worker(s) whom they hold responsible, or the violence may be aimed randomly at any staff member(s) of the medical facility.

Effects of Violence on the Victim

The trauma caused by physical assault varies with the nature of the attack and the weapons employed. Bruises and cuts on the hands and forearms are common when the victim has tried to defend himself or herself. Since the face and head are frequent targets, bruises and fractures of the facial bones are common; these can be traumatic psychologically because the swelling and ecchymoses are so visible and may take weeks to disappear (Mezey and Shepherd 1994).

The psychological effects may be more troublesome than the physical trauma, especially when a health worker has been assaulted by a patient. The victims may experience a loss of composure and self-confidence in their professional competence accompanied by a sense of guilt at having provoked the attack or having failed to detect that it was coming. Unfocused or directed anger may persist at the apparent rejection of their well-intended professional efforts, and there may be a persistent loss of confidence in themselves as well as a lack of trust in their co-workers and supervisors that can interfere with work performance. All this may be accompanied by insomnia, nightmares, diminished or increased appetite, increased consumption of tobacco, alcohol and/or drugs, social withdrawal and absenteeism from the job (Mezey and Shepherd 1994).

Post-traumatic stress disorder is a specific psychological syndrome (PTSD) that may develop after major disasters and instances of violent assault, not only in those directly involved in the incident but also in those who have witnessed it. While usually associated with life-threatening or fatal incidents, PTSD may occur after relatively trivial attacks that are perceived as life-threatening (Foa and Rothbaum 1992). The symptoms include: re-experiencing the incident through recurrent and intrusive recollections (“flashbacks”) and nightmares, persistent feelings of arousal and anxiety including muscular tension, autonomic hyperactivity, loss of concentration, and exaggerated reactivity. There is often conscious or unconscious avoidance of circumstances that recall the incident. There may be a long period of disability but the symptoms usually respond to supportive psychotherapy. They can often be prevented by a post-incident debriefing conducted as soon as possible after the incident, followed, when needed, by short-term counselling (Foa and Rothbaum 1992).

After the Incident

Interventive measures to be taken immediately after the incident include:

Care of the victim

Appropriate first-aid and medical care should be provided as quickly as possible to all injured individuals. For possible medico-legal purposes (e.g., criminal or civil actions against the assailant) the injuries should be described in detail and, if possible, photographed.

Clean-up of the workplace

Any damage or debris in the workplace should be cleaned up, and any equipment that was involved should be checked to make sure that the safety and cleanliness of the workplace have been fully restored (SEIU 1995).

Post-incident debriefing

As soon as possible, all those involved in or witnessing the incident should participate in a post-incident debriefing or a “trauma-crisis counselling” session conducted by an appropriately qualified staff member or an outside consultant. This will not only provide emotional support and identify those for whom referral for one-on-one counselling may be advisable, but also enable the collection of details of exactly what has happened. Where necessary, the counselling may be supplemented by the formation of a peer support group (CAL/OSHA 1995).

Reporting

A standardized report form should be completed and submitted to the proper individual in the organization and, when appropriate, to the police in the community. A number of sample forms that may be adapted to the needs of a particular organization have been designed and published (Unison 1991, MSF 1993, SEIU 1995). Aggregating and analysing incident report forms will provide epidemiological information that may identify risk factors for violence in the particular workplace and point the way to suitable preventive interventions.

Investigating the incident

Each reported incident of alleged violence, however trivial it may seem, should be investigated by a designated properly trained individual. (Assignment for such investigations may be made by the joint labour/management safety and health committee, where one exists.) The investigation should be aimed at identifying the cause(s) of the incident, the person(s) involved, what, if any, disciplinary measures should be invoked, and what may be done to prevent recurrences. Failure to conduct an impartial and effective investigation is a signal of management’s disinterest and a lack of concern for employees’ health and welfare.

Employer support

Victims and observers of the incident should be assured that they will not be subject to discrimination or any other form of reprisal for reporting it. This is especially important when the alleged assailant is the worker’s superior.

Depending on the regulations extant in the particular jurisdiction, the nature and extent of any injuries, and the duration of any absence from work, the employee may be eligible for workers’ compensation benefits. In such cases, the appropriate claim forms should be filed promptly.

When appropriate, a report should be filed with the local law enforcement agency. When needed, the victim may be provided with legal advice on pressing charges against the assailant, and assistance in dealing with the media.

Union Involvement

A number of unions have been playing a prominent role in dealing with workplace violence, most notably those representing workers in the health care and service industries, such as the Service Employees International Union (SEIU) in the United States, and Management, Science and Finance (MSF) and Unison in the UK. Through the development of guidelines and the publication of fact sheets, bulletins and pamphlets, they have focused on the education of workers, their representatives and their employers about the importance of violence in the workplace, how to deal with it, and how to prevent it. They have acted as advocates for members who have been victims to ensure that their complaints and allegations of violence are given appropriate consideration without threats of reprisal, and that they receive all of the benefits to which they may be entitled. Unions also advocate with employers’ and trade associations and government agencies on behalf of policies, rules and regulations intended to reduce the prevalence of violence in the workplace.

Threats of Violence

All threats of violence should be taken seriously, whether aimed at particular individuals or at the organization as a whole. First, steps must be taken to protect the targeted individual(s). Then, where possible, the assailant should be identified. If that person is not in the workforce, the local law enforcement agencies should be notified. If he or she is in the organization, it may be desirable to consult a qualified mental health professional to guide the handling of the situation and/or deal directly with the assailant.

Preventive Strategies

Preventing violence in the workplace is fundamentally the employer’s responsibility. Ideally, a formal policy and programme will have been developed and implemented before victimization occurs. This is a process that should involve not only the appropriate individuals in human resources/personnel, security, legal affairs, and employee health and safety departments, but also line managers and shop stewards or other employee representatives. A number of guides for such an exercise have been published (see  table 4). They are generic and are intended to be tailored to the circumstances of a particular workplace or industry. Their common denominators include:

Table 4. Guides for programmes to prevent workplace violence

Establishing a policy

A policy explicitly outlawing discriminatory and abusive behaviour and the use of violence for dispute resolution, accompanied by specified disciplinary measures for infractions (up to and including dismissal), should be formulated and published.

Risk assessment

An inspection of the workplace, supplemented by analysis of prior incidents and/or information from employee surveys, will enable an expert to assess risk factors for violence and suggest preventive interventions. Examination of the prevailing style of management and supervision and the organization of work may disclose high levels of work stress that may precipitate violence. Study of interactions with clients, customers or patients may reveal features that may generate needless anxiety, frustration and anger, and precipitate violent reactions.

Workplace modifications to reduce crime

Guidance from police or private security experts may suggest changes in work procedures and in the layout and furnishing of the workplace that will make it a less attractive target for robbery attempts. In the United States, the Virginia Department of Criminal Justice has been using Crime Prevention Through Environmental Design (CPTED), a model approach developed by a consortium of the schools of architecture in the state that includes: changes in interior and exterior lighting and landscaping with particular attention to parking areas, stairwells and restrooms; making sales and waiting areas visible from the street; use of drop safes or time-release safes to hold cash; alarm systems, television monitors and other security equipment (Malcan 1993). CPTED has been successfully applied in convenience stores, banks (particularly in relation to automatic teller machines which may be accessed around the clock), schools and universities, and in the Washington, DC, Metro subway system.

In New York City, where robbery and killing of taxi drivers is relatively frequent compared to other large cities, the Taxi and Limousine Commission issued regulations that mandated the insertion of a transparent, bullet-resistant partition between the driver and passengers in the rear seat, a bullet-proof plate in the back of the driver’s seat, and an external distress signal light that could be turned on by the driver while remaining invisible to those inside the cab (NYC/TLC 1994). (There has been a spate of head and facial injuries among rear seat passengers who were not wearing seat belts and were thrown forward against the partition when the cab stopped suddenly.)

Where work involves interaction with customers or patients, employee safety may be enhanced by interposing barriers such as counters, desks or tables, transparent, shatter-proof partitions, and locked doors with shatter-proof windows (CAL/OSHA 1993). Furniture and equipment can be arranged to avoid entrapment of the employee and, where privacy is important, it should not be maintained at the expense of isolating the employee with a potentially aggressive or violent individual in a closed or secluded area.

Security systems

Every workplace should have a well-designed security system. Intrusion of strangers may be reduced by limiting entry to a designated reception area where visitors may have an identity check and receive ID badges indicating the areas to be visited. In some situations, it may be advisable to use metal detectors to identify visitors carrying concealed weapons.

Electronic alarm systems triggered by strategically located “panic buttons” can provide audible and/or visual signals that can alert co-workers to danger and summon help from a nearby security station. Such alarm systems may also be rigged to summon local police. However, they are of little use if guards and co-workers have not been trained to respond promptly and properly. Television monitors can not only provide protective surveillance but also record any incidents as they occur, and may help identify the perpetrator. Needless to say, such electronic systems are of little use unless they are maintained properly and tested at frequent intervals to ensure that they are in working order.

Two-way radios and cellular telephones can provide a measure of security for field personnel and those who are working alone. They also provide a means of reporting their location and, when necessary, summoning medical and other forms of assistance.

Work practice controls

Work practices should be reviewed periodically and modified to minimize the build-up of work stress. This involves attention to work schedules, work load, job content, and monitoring of work performance. Adequate staffing levels should be maintained in high-risk work areas both to discourage violent behaviour and to deal with it when it occurs. Adjustment of staffing levels to cope with peak flows of clients or patients will help to minimize irritating delays and crowding of work areas.

Staff training

Workers and supervisors should be trained to recognize rising tension and anger and in non-violent methods of defusing them. Training involving role-playing exercises will help employees to cope with overly aggressive or abusive individuals without being confrontational. In  some  situations,  training  employees  in  self-defence may be indicated, but there is the danger that this will breed a level of self-confidence that will lead them to delay or entirely neglect calling for available help.

Security guards, staff in psychiatric or penal institutions, and others likely to be involved with physically violent individuals should be trained to subdue and restrain them with minimal risk of injury to others or to themselves (SEIU 1995). However, according to Unison (1991), training can never be a substitute for good work organization and the provision of adequate security.

Employee assistance programmes

Employee assistance programmes (EAPs—also known as member assistance programmes, or MAPs, when provided by a union) can be particularly helpful in crisis situations by providing counselling and support to victims and witnesses of violent incidents, referring them to outside mental health professionals when needed, monitoring their progress and overseeing any protective arrangements intended to facilitate their return to work.

EAPs can also counsel employees whose frustration and anger might culminate in violent behaviour because they are overburdened by work-related problems or those arising from life in the family and/or in the community, whose frustration and anger might culminate in violent behaviour. When they have several such clients from a particular area of the workplace, they can (without breaching the confidentiality of personal information essential to their operation) guide managers to making desirable work modifications that will defuse the potential “powder keg” before violence erupts.

Research

Because of the seriousness and complexity of the problem and the paucity of reliable information, research is needed in the epidemiology, causation, prevention and control of violence in society in general and in the workplace. This requires a multidisciplinary effort involving (in addition to experts in occupational safety and health), mental health professionals, social workers, architects and engineers, experts in management science, lawyers, judges and experts in the criminal justice system, authorities on public policy, and others. Urgently needed are expanded and improved systems for the collection and analysis of the relevant data and the development of a consensus on a taxonomy of violence so that information and ideas can be more easily transposed from one discipline to others.

Conclusion

Violence is endemic in the workplace. Homicides are a major cause of work-related deaths, but their impact and cost are considerably outweighed by the prevalence of near misses, non-fatal physical assaults, threats, harassment, aggressive behaviour and abuse, much of which remains undocumented and unreported. Although most of the homicides and many of the assaults occur in conjunction with criminal activities, workplace violence is not just a criminal justice problem. Nor is it solely a problem for mental health professionals and specialists in addictions, although much of it is associated with mental illness, alcoholism and drug abuse. It requires a coordinated effort by experts in a broad variety of disciplines, led by occupational health and safety professionals, and aimed at developing, validating and implementing a coherent set of strategies for intervention and prevention, keeping in mind that the diversity in workers, jobs and industries dictates an ability to tailor them to the unique characteristics of a particular workforce and the organization that employs it.

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Introduction

Ergonomics standards can take many forms, such as regulations which are promulgated on a national level, or guidelines and standards instituted by international organizations. They play an important role in improving the usability of systems. Design and performance standards give managers confidence that the systems they buy will be capable of being used productively, efficiently, safely and comfortably. They also provide users with a benchmark by which to judge their own working conditions. In this article we focus on the International Organization for Standardization (ISO) ergonomics standard 9241 (ISO 1992) because it provides important, internationally recognized, criteria for selecting or designing VDU equipment and systems. ISO carries out its work through a series of technical committees, one of which is ISO TC 159 SC4 Ergonomics of Human System Interaction Committee, which is responsible for ergonomics standards for situations in which human beings and technological systems interact. Its members are representatives of the national standards bodies of member countries and meetings involve national delegations in discussing and voting on resolutions and technical documents. The primary technical work of the committee takes place in eight Working Groups (WGs), each of which has responsibility for different work items listed in figure 1. This sub-committee has developed ISO 9241.

Figure 1. Technical Working Groups of the Ergonomics of Human System Interaction Technical Committee (ISO TC 159 SC4). ISO 9241: Five working groups broke down the “parts” of the standard to those listed below. This illustration shows the correspondence between the parts of the standard and the various aspects of the workstation with which they are concerned

 The work of the ISO has major international importance. Leading manufacturers pay great heed to ISO specifications. Most producers of VDUs are international corporations. It is obvious that the best and most effective solutions to workplace design problems from the international manufacturers’ point of view should be agreed upon internationally. Many regional authorities, such as the European Standardization Organization (CEN) have adopted ISO standards wherever appropriate. The Vienna Agreement, signed by the ISO and CEN, is the official instrument which ensures effective collaboration between the two organizations. As different parts of ISO 9241 are approved and published as international standards, they are adopted as European standards and become part of EN 29241. Since CEN standards replace national standards in the European Union (EU) and the European Free Trade Agreement (EFTA) Member States, the significance of ISO standards in Europe has grown, and, in turn, has also increased pressure on the ISO to efficiently produce standards and guidelines for VDUs.

User performance standards

An alternative to product standards is to develop user performance standards. Thus, rather than specify a product feature such as character height which it is believed will result in a legible display, standards makers develop procedures for testing directly such characteristics as legibility. The standard is then stated in terms of the user performance required from the equipment and not in terms of how that is achieved. The performance measure is a composite including speed and accuracy and the avoidance of discomfort.

User performance standards have a number of advantages; they are

• relevant to the real problems experienced by users

• tolerant of developments in the technology

• flexible enough to cope with interactions between factors.

However, user performance standards can also suffer a number of disadvantages. They cannot be totally complete and scientifically valid in all cases, but do represent reasonable compromises, which require significant time to obtain the agreement of all the parties involved in standards-setting.

Coverage and Use of ISO 9241

The VDU ergonomics requirements standard, ISO 9241, provides detail on ergonomic aspects of products, and on assessing the ergonomic properties of a system. All references to ISO 9241 also apply to EN 29241. Some parts provide general guidance to be considered in the design of equipment, software and tasks. Other parts include more specific design guidance and requirements relevant to current technology, since such guidance is useful to designers. In addition to product specifications, ISO 9241 emphasizes the need to specify factors affecting user performance, including how to assess user performance in order to judge whether or not a system is appropriate to the context in which it will be used.

ISO 9241 has been developed with office-based tasks and environments in mind. This means that in other specialized environments some acceptable deviation from the standard may be needed. In many cases, this adaptation of the office standard will achieve a more satisfactory result than the “blind” specification or testing of an isolated standard specific to a given situation. Indeed, one of the problems with VDU ergonomics standards is that the technology is developing faster than standards makers can work. Thus it is quite possible that a new device may fail to meet the strict requirements in an existing standard because it approaches the need in question in a way radically different from any that were foreseen when the original standard was written. For example, early standards for character quality on a display assumed a simple dot matrix construction. Newer more legible fonts would have failed to meet the original requirement because they would not have the specified number of dots separating them, a notion inconsistent with their design.

Unless standards are specified in terms of the performance to be achieved, the users of ergonomics standards must allow suppliers to meet the requirement by demonstrating that their solution provides equivalent or superior performance to achieve the same objective.

The use of the ISO 9241 standard in the specification and procurement process places display screen ergonomics issues firmly on management’s agenda and helps to ensure proper consideration of these issues by both procurer and supplier. The standard is therefore a useful part of the responsible employer’s strategy for protecting the health, safety and productivity of display screen users.

General issues

ISO 9241 Part 1 General introduction explains the principles underlying the multipart standard. It describes the user performance approach and provides guidance on how to use the standard and on how conformance to parts of ISO 9241 should be reported.

ISO 9241 Part 2 Guidance on task requirements provides guidance on job and task design for those responsible for planning VDU work in order to enhance the efficiency and the well-being of individual users by applying practical ergonomic knowledge to the design of office VDU tasks. Objectives and characteristics of task design are also discussed (see figure 2) and the standard describes how task requirements may be identified and specified within individual organizations and can be incorporated into the organization’s system design and implementation process.

Figure 2. Guidance and task requirements

Case Study: Display Screen Equipment Directive (90/270/EEC)

The Display Screen Directive is one in a series of “daughter”directives dealing with specific aspects of health and safety. The directives form part of the European Union’s programme for promoting health and safety in the single market. The “parent” or “Framework” Directive (89/391/EEC) sets out the general principles of the Community’s approach to Health and Safety. These common principles include the avoidance of risk, where possible, by eliminating the source of the risk and the encouragement of collective protective measures instead of individual protective measures.

Where risk is unavoidable, it must be properly evaluated by people with the relevant skills and measures must be taken which are appropriate to the extent of the risk. Thus if the assessment shows that the level of risk is slight, informal measures may be entirely adequate. However, where significant risk is identified, then stringent measures must be taken. The Directive itself only placed obligations on Member States of the EU, not on individual employers or manufacturers. The Directive required Member States to transpose the obligations into appropriate national laws, regulations and administrative provisions. These in turn place obligations on employers to ensure a minimum level of health and safety for display screen users.

Hardware and environmental ergonomics issues

Display screen

ISO 9241 (EN 29241) Part 3 Visual display requirements specifies the ergonomic requirements for display screens which ensure that they can be read comfortably, safely and efficiently to perform office tasks. Although it deals specifically with displays used in offices, the guidance is appropriate to specify for most applications which require general purpose displays. A user performance test which, once approved, can serve as the basis for performance testing and will become an alternate route to compliance for VDUs.

ISO 9241 Part 7 Display requirements with reflections. The purpose of this part is to specify methods of measurement of glare and reflections from the surface of display screens, including those with surface treatments. It is aimed at display manufacturers who wish to ensure that anti-reflection treatments do not detract from image quality.

ISO 9241 Part 8 Requirements for displayed colours. The purpose of this part is to deal with the requirements for multicolour displays which are largely in addition to the monochrome requirements in Part 3, requirements for visual display in general.

Keyboard and other input devices

ISO 9241 Part 4 Keyboard requirements requires that the keyboard should be tiltable, separate from the display and easy to use without causing fatigue in the arms or hands. This standard also specifies the ergonomic design characteristics of an alphanumeric keyboard which may be used comfortably, safely and efficiently to perform office tasks. Again, although Part 4 is a standard to be used for office tasks, it is appropriate to most applications which require general purpose alphanumeric keyboards. Design specifications and an alternative performance test method of compliance are included.

ISO 9241 Part 9 Requirements for non-keyboard input devices specifies the ergonomic requirements from such devices as the mouse and other pointing devices which may be used in conjunction with a visual display unit. It also includes a performance test.

Workstations

ISO 9241 Part 5 Workstation layout and postural requirements facilitates efficient operation of the VDU and encourages the user to adopt a comfortable and healthy working posture. The requirements for a healthy, comfortable posture are discussed. These include:

• the location of frequently used equipment controls, displays and work surfaces within easy reach

• the opportunity to change position frequently

• the avoidance of excessive, frequent and repetitive movements with extreme extension or rotation of the limbs or trunk

• support for the back allowing an angle of 90 degrees to 110 degrees between back and thighs.

The characteristics of the workplace which promote a healthy and comfortable posture are identified and design guidelines given.

Working environments

ISO 9241 Part 6 Environmental requirements specifies the ergonomic requirements for the visual display unit working environment which will provide the user with comfortable, safe and productive working conditions. It covers the visual, acoustic and thermal environments. The objective is to provide a working environment which should facilitate efficient operation of the VDU and provide the user with comfortable working conditions.

The characteristics of the working environment which influence efficient operation and user comfort are identified, and design guidelines presented. Even when it is possible to control the working environment within strict limits, individuals will differ in their judgements of its acceptability, partly because individuals vary in their preferences and partly because different tasks may require quite different environments. For example, users who sit at VDUs for prolonged periods are far more sensitive to draughts than users whose work involves moving about an office and only working at the VDU intermittently.

VDU work often restricts the opportunities that individuals have for moving about in an office and so some individual control over the environment is highly desirable. Care must be taken in common work areas to protect the majority of users from extreme environments which may be preferred by some individuals.

Software ergonomics and dialogue design

ISO 9241 Part 10 Dialogue principles presents ergonomic principles which apply to the design of dialogues between humans and information systems, as follows:

• suitability for the task

• self-descriptiveness

• controllability

• conformity with user expectations

• error tolerance

• suitability for individualization

• suitability for learning.

The principles are supported by a number of scenarios which indicate the relative priorities and importance of the different principles in practical applications. The starting point for this work was the German DIN 66234 Part 8 Principles of Ergonomic Dialogue Design for Workplaces with Visual Display Units.

ISO 9241 Part 11 Guidance on usability specification and measures helps those involved in specifying or measuring usability by providing a consistent and agreed framework of the key issues and parameters involved. This framework can be used as part of an ergonomic requirements specification and it includes descriptions of the context of use, the evaluation procedures to be carried out and the criterion measures to be satisfied when the usability of the system is to be evaluated.

ISO 9241 Part 12 Presentation of information provides guidance on the specific ergonomics issues involved in representing and presenting information in a visual form. It includes guidance on ways of representing complex information, screen layout and design and the use of windows. It is a useful summary of the relevant materials available among the substantial body of guidelines and recommendations which already exist. The information is presented as guidelines without any need for formal conformance testing.

ISO 9241 Part 13 User guidance provides manufacturers with, in effect, guidelines on how to provide guidelines to users. These include documentation, help screens, error handling systems and other aids that are found in many software systems. In assessing the usability of a product in practice, real users should take into account the documentation and guidance provided by the supplier in the form of manuals, training and so on, as well as the specific characteristics of the product itself.

ISO 9241 Part 14 Menu dialogues provides guidance on the design of menu-based systems. It applies to text-based menus as well as to pull-down or pop-up menus in graphical systems. The standard contains a large number of guidelines developed from the published literature and from other relevant research. In order to deal with the extreme variety and complexity of menu-based systems, the standard employs a form of “conditional compliance”. For each guideline, there are criteria to help establish whether or not it is applicable to the system in question. If it is determined that the guidelines are applicable, criteria to establish whether or not the system meets those requirements are provided.

ISO 9241 Part 15 Command dialogues provides guidance for the design of text-based command dialogues. Dialogues are the familiar boxes which come onto the screen and query the VDU user, such as in a search command. The software creates a “dialogue” in which the user must supply the term to be found, and any other relevant specifications about the term, such as its case or format.

ISO 9241 Part 16 Direct manipulation dialogues deals with the design of direct manipulation dialogues and WYSIWYG (What You See Is What You Get) dialogue techniques, whether provided as the sole means of dialogue or combined with some other dialogue technique. It is envisaged that the conditional compliance developed for Part 14 may be appropriate for this mode of interaction also.

ISO 9241 Part 17 Form-filling dialogues is in the very early stages of development.

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Introduction

The development of effective interfaces to computer systems is the fundamental objective of research on human-computer interactions.

An interface can be defined as the sum of the hardware and software components through which a system is operated and users informed of its status. The hardware components include data entry and pointing devices (e.g., keyboards, mice), information-presentation devices (e.g., screens, loudspeakers), and user manuals and documentation. The software components include menu commands, icons, windows, information feedback, navigation systems and messages and so on. An interface’s hardware and software components may be so closely linked as to be inseparable (e.g., function keys on keyboards). The interface includes everything the user perceives, understands and manipulates while interacting with the computer (Moran 1981). It is therefore a crucial determinant of the human-machine relation.

Research on interfaces aims at improving interface utility, accessibility, performance and safety, and usability. For these purposes, utility is defined with reference to the task to be performed. A useful system contains the necessary functions for the completion of tasks users are asked to perform (e.g., writing, drawing, calculations, programming). Accessibility is a measure of an interface’s ability to allow several categories of users—particularly individuals with handicaps, and those working in geographically isolated areas, in constant movement or having both hands occupied—to use the system to perform their activities. Performance, considered here from a human rather than a technical viewpoint, is a measure of the degree to which a system improves the efficiency with which users perform their work. This includes the effect of macros, menu short-cuts and intelligent software agents. The safety of a system is defined by the extent to which an interface allows users to perform their work free from the risk of human, equipment, data, or environmental accidents or losses. Finally, usability is defined as the ease with which a system is learned and used. By extension, it also includes system utility and performance, defined above.

Elements of Interface Design

Since the invention of shared-time operating systems in 1963, and especially since the arrival of the microcomputer in 1978, the development of human-computer interfaces has been explosive (see Gaines and Shaw 1986 for a history). The stimulus for this development has been essentially driven by three factors acting simultaneously:

First, the very rapid evolution of computer technology, a result of advances in electrical engineering, physics and computer science, has been a major determinant of user interface development. It has resulted in the appearance of computers of ever-increasing power and speed, with high memory capacities, high-resolution graphics screens, and more natural pointing devices allowing direct manipulation (e.g., mice, trackballs). These technologies were also responsible for the emergence of microcomputing. They were the basis for the character-based interfaces of the 1960s and 1970s, graphical interfaces of the late 1970s, and multi- and hyper-media interfaces appearing since the mid-1980s based on virtual environments or using a variety of alternate-input recognition technologies (e.g., voice-, handwriting-, and movement-detection). Considerable research and development has been conducted in recent years in these areas (Waterworth and Chignel 1989; Rheingold 1991). Concomitant with these advances was the development of more advanced software tools for interface design (e.g., windowing systems, graphical object libraries, prototyping systems) that greatly reduce the time required to develop interfaces.

Second, users of computer systems play a large role in the development of effective interfaces. There are three reasons for this. First, current users are not engineers or scientists, in contrast to users of the first computers. They therefore demand systems that can be easily learned and used. Second, the age, sex, language, culture, training, experience, skill, motivation and interest of individual users is quite varied. Interfaces must therefore be more flexible and better able to adapt to a range of needs and expectations. Finally, users are employed in a variety of economic sectors and perform a quite diverse spectrum of tasks. Interface developers must therefore constantly reassess the quality of their interfaces.

Lastly, intense market competition and increased safety expectations favour the development of better interfaces. These preoccupations are driven by two sets of partners: on the one hand, software producers who strive to reduce their costs while maintaining product distinctiveness that furthers their marketing goals, and on the other, users for whom the software is a means of offering competitive products and services to clients. For both groups, effective interfaces offer a number of advantages:

For software producers:

• better product image

• increased demand for products

• shorter training times

• lower after-sales service requirements

• solid base upon which to develop a product line

• reduction of the risk of errors and accidents

• reduction of documentation.

For users:

• shorter learning phase

• increased general applicability of skills

• improved use of the system

• increased autonomy using the system

• reduction of the time needed to execute a task

• reduction in the number of errors

• increased satisfaction.

Effective interfaces can significantly improve the health and productivity of users at the same time as they improve the quality and reduce the cost of their training. This, however, requires basing interface design and evaluation on ergonomic principles and practice standards, be they guidelines, corporate standards of major system manufacturers or international standards. Over the years, an impressive body of ergonomic principles and guidelines related to interface design has accumulated (Scapin 1986; Smith and Mosier 1986; Marshall, Nelson and Gardiner 1987; Brown 1988). This multidisciplinary corpus covers all aspects of character-mode and graphical interfaces, as well as interface evaluation criteria. Although its concrete application occasionally poses some problems—for example, imprecise terminology, inadequate information on usage conditions, inappropriate presentation—it remains a valuable resource for interface design and evaluation.

In addition, the major software manufacturers have developed their own guidelines and internal standards for interface design. These guidelines are available in the following documents:

• Apple Human Interface Guidelines (1987)

• Open Look (Sun 1990)

• OSF/Motif Style Guide (1990)

• IBM Common User Access guide to user interface design (1991)

• IBM Advanced Interface Design Reference (1991)

• The Windows interface: An application design guide (Microsoft 1992)

These guidelines attempt to simplify interface development by mandating a minimal level of uniformity and consistency between interfaces used on the same computer platform. They are precise, detailed, and quite comprehensive in several respects, and offer the additional advantages of being well-known, accessible and widely used. They are the de facto design standards used by developers, and are, for this reason, indispensable.

Furthermore, the International Organization for Standardization (ISO) standards are also very valuable sources of information about interface design and evaluation. These standards are primarily concerned with ensuring uniformity across interfaces, regardless of platforms and applications. They have been developed in collaboration with national standardization agencies, and after extensive discussion with researchers, developers and manufacturers. The main ISO interface design standard is ISO 9241, which describes ergonomic requirements for visual display units. It is comprised of 17 parts. For example, parts 14, 15, 16 and 17 discuss four types of human-computer dialogue—menus, command languages, direct manipulation, and forms. ISO standards should take priority over other design principles and guidelines. The following sections discuss the principles which should condition interface design.

A Design Philosophy Focused on the User

Gould and Lewis (1983) have proposed a design philosophy focused on the video display unit user. Its four principles are:

1. Immediate and continuous attention to users. Direct contact with users is maintained, in order to better understand their characteristics and tasks.
2. Integrated design. All aspects of usability (e.g., interface, manuals, help systems) are developed in parallel and placed under centralized control.
3. Immediate and continuous evaluation by users. Users test the interfaces or prototypes early on in the design phase, under simulated work conditions. Performance and reactions are measured quantitatively and qualitatively.
4. Iterative design. The system is modified on the basis of the results of the evaluation, and the evaluation cycle started again.

These principles are explained in further detail in Gould (1988). Very relevant when they were first published in 1985, fifteen years later they remain so, due to the inability to predict the effectiveness of interfaces in the absence of user testing. These principles constitute the heart of user-based development cycles proposed by several authors in recent years (Gould 1988; Mantei and Teorey 1989; Mayhew 1992; Nielsen 1992; Robert and Fiset 1992).

The rest of this article will analyse five stages in the development cycle that appear to determine the effectiveness of the final interface.

Task Analysis

Ergonomic task analysis is one of the pillars of interface design. Essentially, it is the process by which user responsibilities and activities are elucidated. This in turn allows interfaces compatible with the characteristics of users’ tasks to be designed. There are two facets to any given task:

1. The nominal task, corresponding to the organization’s formal definition of the task. This includes objectives, procedures, quality control, standards and tools.
2. The real task, corresponding to the users’ decisions and behaviours necessary for the execution of the nominal task.

The gap between nominal and real tasks is inevitable and results from the failure of nominal tasks to take into account variations and unforeseen circumstances in the work flow, and differences in users’ mental representations of their work. Analysis of the nominal task is insufficient for a full understanding of users’ activities.

Activity analysis examines elements such as work objectives, the type of operations performed, their temporal organization (sequential, parallel) and frequency, the operational modes relied upon, decisions, sources of difficulty, errors and recovery modes. This analysis reveals the different operations performed to accomplish the task (detection, searching, reading, comparing, evaluating, deciding, estimating, anticipating), the entities manipulated (e.g., in process control, temperature, pressure, flow-rate, volume) and the relation between operators and entities. The context in which the task is executed conditions these relations. These data are essential for the definition and organization of the future system’s features.

At its most basic, task analysis is composed of data collection, compilation and analysis. It may be performed before, during or after computerization of the task. In all cases, it provides essential guidelines for interface design and evaluation. Task analysis is always concerned with the real task, although it may also study future tasks through simulation or prototype testing. When performed prior to computerization, it studies “external tasks” (i.e., tasks external to the computer) performed with the existing work tools (Moran 1983). This type of analysis is useful even when computerization is expected to result in major modification of the task, since it elucidates the nature and logic of the task, work procedures, terminology, operators and tasks, work tools and sources of difficulty. In so doing, it provides the data necessary for task optimization and computerization.

Task analysis performed during task computerization focuses on “internal tasks”, as performed and represented by the computer system. System prototypes are used to collect data at this stage. The focus is on the same points examined in the previous stage, but from the point of view of the computerization process.

Following task computerization, task analysis also studies internal tasks, but analysis now focuses on the final computer system. This type of analysis is often performed to evaluate existing interfaces or as part of the design of new ones.

Hierarchical task analysis is a common method in cognitive ergonomics that has proven very useful in a wide variety of fields, including interface design (Shepherd 1989). It consists of the division of tasks (or main objectives) into sub-tasks, each of which can be further subdivided, until the required level of detail is attained. If data is collected directly from users (e.g., through interviews, vocalization), hierarchical division can provide a portrait of users’ mental mapping of a task. The results of the analysis can be represented by a tree diagram or table, each format having its advantages and disadvantages.

User Analysis

The other pillar of interface design is the analysis of user characteristics. The characteristics of interest may relate to user age, sex, language, culture, training, technical or computer-related knowledge, skills or motivation. Variations in these individual factors are responsible for differences within and between groups of users. One of the key tenets of interface design is therefore that there is no such thing as the average user. Instead, different groups of users should be identified and their characteristics understood. Representatives of each group should be encouraged to participate in the interface design and evaluation processes.

On the other hand, techniques from psychology, ergonomics and cognitive engineering can be used to reveal information on user characteristics related to perception, memory, cognitive mapping, decision-making and learning (Wickens 1992). It is clear that the only way to develop interfaces that are truly compatible with users is to take into account the effect of differences in these factors on user capacities, limits and ways of operating.

Ergonomic studies of interfaces have focused almost exclusively on users’ perceptual, cognitive and motor skills, rather than on affective, social or attitudinal factors, although work in the latter fields has become more popular in recent years. (For an integrated view of humans as information-processing systems see Rasmussen 1986; for a review of user-related factors to consider when designing interfaces see Thimbleby 1990 and Mayhew 1992). The following paragraphs review the four main user-related characteristics that should be taken into account during interface design.

Mental representation

The mental models users construct of the systems they use reflect the manner in which they receive and understand these systems. These models therefore vary as a function of users’ knowledge and experience (Hutchins 1989). In order to minimize the learning curve and facilitate system use, the conceptual model upon which a system is based should be similar to users’ mental representation of it. It should be recognized however that these two models are never identical. The mental model is characterized by the very fact that it is personal (Rich 1983), incomplete, variable from one part of the system to another, possibly in error on some points and in constant evolution. It plays a minor role in routine tasks but a major one in non-routine ones and during diagnosis of problems (Young 1981). In the latter cases, users will perform poorly in the absence of an adequate mental model. The challenge for interface designers is to design systems whose interaction with users will induce the latter to form mental models similar to the system’s conceptual model.

Learning

Analogy plays a large role in user learning (Rumelhart and Norman 1983). For this reason, the use of appropriate analogies or metaphors in the interface facilitates learning, by maximizing the transfer of knowledge from known situations or systems. Analogies and metaphors play a role in many parts of the interface, including the names of commands and menus, symbols, icons, codes (e.g., shape, colour) and messages. When pertinent, they greatly contribute to rendering interfaces natural and more transparent to users. On the other hand, when they are irrelevant, they can hinder users (Halasz and Moran 1982). To date, the two metaphors used in graphical interfaces are the desktop and, to a lesser extent, the room.

Users generally prefer to learn new software by using it immediately rather than by reading or taking a course—they prefer action-based learning in which they are cognitively active. This type of learning does, however, present a few problems for users (Carroll and Rosson 1988; Robert 1989). It demands an interface structure which is compatible, transparent, consistent, flexible, natural-appearing and fault tolerant, and a feature set which ensures usability, feedback, help systems, navigational aides and error handling (in this context, “errors” refer to actions that users wish to undo). Effective interfaces give users some autonomy during exploration.

Developing knowledge

User knowledge develops with increasing experience, but tends to plateau rapidly. This means that interfaces must be flexible and capable of responding simultaneously to the needs of users with different levels of knowledge. Ideally, they should also be context sensitive and provide personalized help. The EdCoach system, developed by Desmarais, Giroux and Larochelle (1993) is such an interface. Classification of users into beginner, intermediate and expert categories is inadequate for the purpose of interface design, since these definitions are too static and do not account for individual variations. Information technology capable of responding to the needs of different types of users is now available, albeit at the research, rather than commercial, level (Egan 1988). The current rage for performance-support systems suggests intense development of these systems in coming years.

Unavoidable errors

Finally, it should be recognized that users make mistakes when using systems, regardless of their skill level or the quality of the system. A recent German study by Broadbeck et al. (1993) revealed that at least 10% of the time spent by white-collar workers working on computers is related to error management. One of the causes of errors is users’ reliance on correction rather than prevention strategies (Reed 1982). Users prefer acting rapidly and incurring errors that they must subsequently correct, to working more slowly and avoiding errors. It is essential that these considerations be taken into account when designing human-computer interfaces. In addition, systems should be fault tolerant and should incorporate effective error management (Lewis and Norman 1986).

Needs Analysis

Needs analysis is an explicit part of Robert and Fiset’s development cycle (1992), it corresponds to Nielsen’s functional analysis and is integrated into other stages (task, user or needs analysis) described by other authors. It consists of the identification, analysis and organization of all the needs that the computer system can satisfy. Identification of features to be added to the system occurs during this process. Task and user analysis, presented above, should help define many of the needs, but may prove inadequate for the definition of new needs resulting from the introduction of new technologies or new regulations (e.g., safety). Needs analysis fills this void.

Needs analysis is performed in the same way as functional analysis of products. It requires the participation of a group of people interested by the product and possessing complementary training, occupations or work experience. This can include future users of the system, supervisors, domain experts and, as required, specialists in training, work organization and safety. Review of the scientific and technical literature in the relevant field of application may also be performed, in order to establish the current state of the art. Competitive systems used in similar or related fields can also be studied. The different needs identified by this analysis are then classified, weighted and presented in a format appropriate for use throughout the development cycle.

Prototyping

Prototyping is part of the development cycle of most interfaces and consists of the production of a preliminary paper or electronic model (or prototype) of the interface. Several books on the role of prototyping in human-computer interaction are available (Wilson and Rosenberg 1988; Hartson and Smith 1991; Preece et al. 1994).

Prototyping is almost indispensable because:

1. Users have difficulty evaluating interfaces on the basis of functional specifications—the description of the interface is too distant from the real interface, and evaluation too abstract. Prototypes are useful because they allow users to see and use the interface and directly evaluate its usefulness and usability.
2. It is practically impossible to construct an adequate interface on the first try. Interfaces must be tested by users and modified, often repeatedly. To overcome this problem, paper or interactive prototypes that can be tested, modified or rejected are produced and refined until a satisfactory version is obtained. This process is considerably less expensive than working on real interfaces.

From the point of view of the development team, prototyping has several advantages. Prototypes allow the integration and visualization of interface elements early on in the design cycle, rapid identification of detailed problems, production of a concrete and common object of discussion in the development team and during discussions with clients, and simple illustration of alternative solutions for the purposes of comparison and internal evaluation of the interface. The most important advantage is, however, the possibility of having users evaluate prototypes.

Inexpensive and very powerful software tools for the production of prototypes are commercially available for a variety of platforms, including microcomputers (e.g., Visual Basic and Visual C++ (™Microsoft Corp.), UIM/X (™Visual Edge Software), HyperCard (™Apple Computer), SVT (™SVT Soft Inc.)). Readily available and relatively easy to learn, they are becoming widespread among system developers and evaluators.

The integration of prototyping completely changed the interface development process. Given the rapidity and flexibility with which prototypes can be produced, developers now tend to reduce their initial analyses of task, users and needs, and compensate for these analytical deficiencies by adopting longer evaluation cycles. This assumes that usability testing will identify problems and that it is more economical to prolong evaluation than to spend time on preliminary analysis.

Evaluation of Interfaces

User evaluation of interfaces is an indispensable and effective way to improve interfaces’ usefulness and usability (Nielsen 1993). The interface is almost always evaluated in electronic form, although paper prototypes may also be tested. Evaluation is an iterative process and is part of the prototype evaluation-modification cycle which continues until the interface is judged acceptable. Several cycles of evaluation may be necessary. Evaluation may be performed in the workplace or in usability laboratories (see the special edition of Behaviour and Information Technology (1994) for a description of several usability laboratories).

Some interface evaluation methods do not involve users; they may be used as a complement to user evaluation (Karat 1988; Nielsen 1993; Nielsen and Mack 1994). A relatively common example of such methods consists of the use of criteria such as compatibility, consistency, visual clarity, explicit control, flexibility, mental workload, quality of feedback, quality of help and error handling systems. For a detailed definition of these criteria, see Bastien and Scapin (1993); they also form the basis of an ergonomic questionnaire on interfaces (Shneiderman 1987; Ravden and Johnson 1989).

Following evaluation, solutions must be found to problems that have been identified, modifications discussed and implemented, and decisions made concerning whether a new prototype is necessary.

Conclusion

This discussion of interface development has highlighted the major stakes and broad trends in the field of human-computer interaction. In summary, (a) task, user, and needs analysis play an essential role in understanding system requirements and, by extension, necessary interface features; and (b) prototyping and user evaluation are indispensable for the determination of interface usability. An impressive body of knowledge, composed of principles, guidelines and design standards, exists on human-computer interactions. Nevertheless, it is currently impossible to produce an adequate interface on the first try. This constitutes a major challenge for the coming years. More explicit, direct and formal links must be established between analysis (task, users, needs, context) and interface design. Means must also be developed to apply current ergonomic knowledge more directly and more simply to the design of interfaces.

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Introduction

Computers provide efficiency, competitive advantages and the ability to carry out work processes that would not be possible without their use. Areas such as manufacturing process control, inventory management, records management, complex systems control and office automation have all benefited from automation. Computerization requires substantial infrastructure support in order to function properly. In addition to architectural and electrical changes needed to accommodate the machines themselves, the introduction of computerization requires changes in employee knowledge and skills, and application of new methods of managing work. The demands placed on jobs which use computers can be very different from those of traditional jobs. Often computerized jobs are more sedentary and may require more thinking and mental attention to tasks, while at the same time require less physical energy expenditure. Production demands can be high, with constant work pressure and little room for decision-making.

The economic advantages of computers at work have overshadowed associated potential health, safety and social problems for workers, such as job loss, cumulative trauma disorders and increased mental stress. The transition from more traditional forms of work to computerization has been difficult in many workplaces, and has resulted in significant psychosocial and sociotechnical problems for the workforce.

Psychosocial Problems Specific to VDUs

Research studies (for example, Bradley 1983 and 1989; Bikson 1987; Westlander 1989; Westlander and Aberg 1992; Johansson and Aronsson 1984; Stellman et al. 1987b; Smith et al. 1981 and 1992a) have documented how the introduction of computers into the workplace has brought substantial changes in the process of work, in social relationships, in management style and in the nature and content of job tasks. In the 1980s, the implementation of the technological changeover to computerization was most often a “top-down” process in which employees had no input into the decisions regarding the new technology or the new work structures. As a result, many industrial relations, physical and mental health problems arose.

Experts disagree on the success of changes that are occurring in offices, with some arguing that computer technology improves the quality of work and enhances productivity (Strassmann 1985), while others compare computers to earlier forms of technology, such as assembly-line production that also make working conditions worse and increase job stress (Moshowitz 1986; Zuboff 1988). We believe that visual display unit (VDU) technology does affect work in various ways, but technology is only one element of a larger work system that includes the individual, tasks, environment and organizational factors.

Conceptualizing Computerized Job Design

Many working conditions jointly influence the VDU user. The authors have proposed a comprehensive job design model which illustrates the various facets of working conditions which can interact and accumulate to produce stress (Smith and Carayon-Sainfort 1989). Figure 1 illustrates this conceptual model for the various elements of a work system that can exert loads on workers and may result in stress. At the centre of this model is the individual with his/her unique physical characteristics, perceptions, personality and behaviour. The individual uses technologies to perform specific job tasks. The nature of the technologies, to a large extent, determines performance and the skills and knowledge needed by the worker to use the technology effectively. The requirements of the task also affect the required skill and knowledge levels needed. Both the tasks and technologies affect the job content and the mental and physical demands. The model also shows that the tasks and technologies are placed within the context of a work setting that comprises the physical and the social environment. The overall environment itself can affect comfort, psychological moods and attitudes. Finally, the organizational structure of work defines the nature and level of individual involvement, worker interactions, and levels of control. Supervision and standards of performance are all affected by the nature of the organization.

Figure 1. Model of working conditions and their impact on the individual

This model helps to explain relationships between job requirements, psychological and physical loads and resulting health strains. It represents a systems concept in which any one element can influence any other element, and in which all elements interact to determine the way in which work is accomplished and the effectiveness of the work in achieving individual and organizational needs and goals. The application of the model to the VDU workplace is described below.

Environment

Physical environmental factors have been implicated as job stressors in the office and elsewhere. General air quality and housekeeping contribute, for example, to sick building syndrome and other stress responses (Stellman et al. 1985; Hedge, Erickson and Rubin 1992.) Noise is a well-known environmental stressor which can cause increases in arousal, blood pressure, and negative psychological mood (Cohen and Weinstein 1981). Environmental conditions that produce sensory disruption and make it more difficult to carry out tasks increase the level of worker stress and emotional irritation are other examples (Smith et al. 1981; Sauter et al. 1983b).

Task 

With the introduction of computer technology, expectations regarding performance increase. Additional pressure on workers is created because they are expected to perform at a higher level all the time. Excessive workload and work pressure are significant stressors for computer users (Smith et al. 1981; Piotrkowski, Cohen and Coray 1992; Sainfort 1990). New types of work demands are appearing with the increasing use of computers. For instance, cognitive demands are likely to be sources of increased stress for VDU users (Frese 1987). These are all facets of job demands.

Electronic Monitoring of Employee Performance

The use of electronic methods to monitor employee work performance has increased substantially with the widespread use of personal computers which make such monitoring quick and easy. Monitoring provides information which can be used by employers to better manage technological and human resources. With electronic monitoring it is possible to pinpoint bottlenecks, production delays and below average (or below standard) performance of employees in real time. New electronic communication technologies have the capability of tracking the performance of individual elements of a communication system and of pinpointing individual worker inputs. Such work elements as data entry into computer terminals, telephone conversations, and electronic mail messages can all be examined through the use of electronic surveillance.

Electronic monitoring increases management control over the workforce, and may lead to organisational management approaches that are stressful. This raises important issues about the accuracy of the monitoring system and how well it represents worker contributions to the employer’s success, the invasion of worker privacy, worker versus technology control over job tasks, and the implications of management styles that use monitored information to direct worker behaviour on the job (Smith and Amick 1989; Amick and Smith 1992; Carayon 1993b). Monitoring can bring about increased production, but it may also produce job stress, absences from work, turnover in the workforce and sabotage. When electronic monitoring is combined with incentive systems for increased production, work-related stress can also be increased (OTA 1987; Smith et al. 1992a). In addition, such electronic performance monitoring raises issues of worker privacy (ILO 1991) and several countries have banned the use of individual performance monitoring.

A basic requirement of electronic monitoring is that work tasks be broken up into activities that can easily be quantified and measured, which usually results in a job design approach that reduces the content of the tasks by removing complexity and thinking, which are replaced by repetitive action. The underlying philosophy is similar to a basic principle of “Scientific Management” (Taylor 1911) that calls for work “simplification.”

In one company, for example, a telephone monitoring capability was included with a new telephone system for customer service operators. The monitoring system distributed incoming telephone calls from customers, timed the calls and allowed for supervisor eavesdropping on employee telephone conversations. This system was instituted under the guise of a work flow scheduling tool for determining the peak periods for telephone calls to determine when extra operators would be needed. Instead of using the monitoring system solely for that purpose, management also used the data to establish work performance standards, (seconds per transaction) and to bring disciplinary action against employees with “below average performance.” This electronic monitoring system introduced a pressure to perform above average because of fear of reprimand. Research has shown that such work pressure is not conducive to good performance but rather can bring about adverse health consequences (Cooper and Marshall 1976; Smith 1987). In fact, the monitoring system described was found to have increased employee stress and lowered the quality of production (Smith et al. 1992a).

Electronic monitoring can influence worker self-image and feelings of self-worth. In some cases, monitoring could enhance feelings of self-worth if the worker gets positive feedback. The fact that management has taken an interest in the worker as a valuable resource is another possible positive outcome. However, both effects may be perceived differently by workers, particularly if poor performance leads to punishment or reprimand. Fear of negative evaluation can produce anxiety and may damage self-esteem and self-image. Indeed electronic monitoring can create known adverse working conditions, such as paced work, lack of worker involvement, reduced task variety and task clarity, reduced peer social support, reduced supervisory support, fear of job loss, or routine work activities, and lack of control over tasks (Amick and Smith 1992; Carayon 1993).

Michael J. Smith

Positive aspects also exist since computers are able to do many of the simple, repetitive tasks that were previously done manually, which can reduce the repetitiveness of the job, increase the content of the job and make it more meaningful. This is not universally true, however, since many new computer jobs, such as data entry, are still repetitive and boring. Computers can also provide performance feedback that is not available with other technologies (Kalimo and Leppanen 1985), which can reduce ambiguity.

Some aspects of computerized work have been linked to decreased control, which has been identified as a major source of stress for clerical computer users. Uncertainty regarding the duration of computer-related problems, such as breakdown and slowdown, can be a source of stress (Johansson and Aronsson 1984; Carayon-Sainfort 1992). Computer-related problems can be particularly stressful if workers, such as airline reservation clerks, are highly dependent on the technology to perform their job.

Technology

The technology being used by the worker often defines his or her ability to accomplish tasks and the extent of physiological and psychological load. If the technology produces either too much or too little workload, increased stress and adverse physical health outcomes can occur (Smith et al. 1981; Johansson and Aronsson 1984; Ostberg and Nilsson 1985). Technology is changing at a rapid pace, forcing workers to adjust their skills and knowledge continuously to keep up. In addition, today’s skills can quickly become obsolete. Technological obsolescence may be due to job de-skilling and impoverished job content or to inadequate skills and training. Workers who do not have the time or resources to keep up with the technology may feel threatened by the technology and may worry about losing their job. Thus, workers’ fears of having inadequate skills to use the new technology are one of the main adverse influences of technology, which training, of course, can help to offset. Another effect of the introduction of technology is the fear of job loss due to increased efficiency of technology (Ostberg and Nilsson 1985; Smith, Carayon and Miezio 1987).

Intensive, repetitive, long sessions at the VDU can also contribute to increased ergonomic stress and strain (Stammerjohn, Smith and Cohen 1981; Sauter et al. 1983b; Smith et al. 1992b) and can create visual or musculoskeletal discomfort and disorders, as described elsewhere in the chapter.

Organizational factors

The organizational context of work can influence worker stress and health. When technology requires new skills, the way in which workers are introduced to the new technology and the organizational support they receive, such as appropriate training and time to acclimatize, has been related to the levels of stress and emotional disturbances experienced (Smith, Carayon and Miezio 1987). The opportunity for growth and promotion in a job (career development) is also related to stress (Smith et al. 1981). Job future uncertainty is a major source of stress for computer users (Sauter et al. 1983b; Carayon 1993a) and the possibility of job loss also creates stress (Smith et al. 1981; Kasl 1978).

Work scheduling, such as shift work and overtime, have been shown to have negative mental and physical health consequences (Monk and Tepas 1985; Breslow and Buell 1960). Shift work is increasingly used by companies that want or need to keep computers running continuously. Overtime is often needed to ensure that workers keep up with the workload, especially when work remains incomplete as a result of delays due to computer breakdown or misfunction.

Computers provide management with the capability to continuously monitor employee performance electronically, which has the potential to create stressful working conditions, such as by increasing work pressure (see the box “Electronic Monitoring”). Negative employee-supervisor relationships and feelings of lack of control can increase in electronically supervised workplaces.

The introduction of VDU technology has affected social relationships at work. Social isolation has been identified as a major source of stress for computer users (Lindström 1991; Yang and Carayon 1993) since the increased time spent working on computers reduces the time that workers have to socialize and receive or give social support. The need for supportive supervisors and co-workers has been well documented (House 1981). Social support can moderate the impact of other stressors on worker stress. Thus, support from colleagues, supervisor or computer staff becomes important for the worker who is experiencing computer-related problems but the computer work environment may, ironically, reduce the level of such social support available.

The individual

A number of personal factors such as personality, physical health status, skills and abilities, physical conditioning, prior experiences and learning, motives, goals and needs determine the physical and psychological effects just described (Levi 1972).

Improving the Psychosocial Characteristics of VDU Work

The first step in making VDU work less stressful is to identify work organization and job design features that can promote psychosocial problems so that they can be modified, always bearing in mind that VDU problems which can lead to job stress are seldom the result of single aspects of the organization or of job design, but rather, are a combination of many aspects of improper work design. Thus, solutions for reducing or eliminating job stress must be comprehensive and deal with many improper work design factors simultaneously. Solutions that focus on only one or two factors will not succeed. (See figure 2.)

Figure 2. Keys to reducing isolation and stress

Improvements in job design should start with the work organization providing a supportive environment for employees. Such an environment enhances employee motivation to work and feelings of security, and it reduces feelings of stress (House 1981). A policy statement that defines the importance of employees within an organization and is explicit on how the organization will provide a supportive environment is a good first step. One very effective means for providing support to employees is to provide supervisors and managers with specific training in methods for being supportive. Supportive supervisors can serve as buffers that “protect” employees from unnecessary organizational or technological stresses.

The content of job tasks has long been recognized as important for employee motivation and productivity (Herzberg 1974; Hackman and Oldham 1976). More recently the relationship between job content and job stress reactions has been elucidated (Cooper and Marshall 1976; Smith 1987). Three main aspects of job content that are of specific relevance to VDU work are task complexity, employee skills and career opportunities. In some respects, these are all related to the concept of developing the motivational climate for employee job satisfaction and psychological growth, which deals with the improvement of employees’ intellectual capabilities and skills, increased ego enhancement or self-image and increased social group recognition of individual achievement.

The primary means for enhancing job content is to increase the skill level for performing job tasks, which typically means enlarging the scope of job tasks, as well as enriching the elements of each specific task (Herzberg 1974). Enlarging the number of tasks increases the repertoire of skills needed for successful task performance, and also increases the number of employee decisions made while defining task sequences and activities. An increase in the skill level of the job content promotes employee self-image of personal worth and of value to the organization. It also enhances the positive image of the individual in his or her social work group within the organization.

Increasing the complexity of the tasks, which means increasing the amount of thinking and decision-making involved, is a logical next step that can be achieved by combining simple tasks into sets of related activities that have to be coordinated, or by adding mental tasks that require additional knowledge and computational skills. Specifically, when computerized technology is introduced, new tasks in general will have requirements that exceed the current knowledge and skills of the employees who are to perform them. Thus there is a need to train employees in the new aspects of the tasks so that they will have the skills to perform the tasks adequately. Such training has more than one benefit, since it not only may improve employee knowledge and skills, and thus enhance performance, but may also enhance employee self-esteem and confidence. Providing training also shows the employee that the employer is willing to invest in his or her skill enhancement, and thus promotes confidence in employment stability and job future.

The amount of control that an employee has over the job has a powerful psychosocial influence (Karasek et al. 1981; Sauter, Cooper and Hurrell 1989). Important aspects of control can be defined by the answers to the questions, “What, how and when?” The nature of the tasks to be undertaken, the need for coordination among employees, the methods to be used to carry out the tasks and the scheduling of the tasks can all be defined by answers to these questions. Control can be designed into jobs at the levels of the task, the work unit and the organization (Sainfort 1991; Gardell 1971). At the task level, the employee can be given autonomy in the methods and procedures used in completing the task.

At the work-unit level, groups of employees can self-manage several interrelated tasks and the group itself can decide on who will perform particular tasks, the scheduling of tasks, coordination of tasks and production standards to meet organizational goals. At the organization level, employees can participate in structured activities that provide input to management about employee opinions or quality improvement suggestions. When the levels of control available are limited, it is better to introduce autonomy at the task level and then work up the organizational structure, insofar as possible (Gardell 1971).

One natural result of computer automation appears to be an increased workload, since the purpose of the automation is to enhance the quantity and quality of work output. Many organizations believe that such an increase is necessary in order to pay for the investment in the automation. However, establishing the appropriate workload is problematic. Scientific methods have been developed by industrial engineers for determining appropriate work methods and workloads (the performance requirements of jobs). Such methods have been used successfully in manufacturing industries for decades, but have had little application in office settings, even after office computerization. The use of scientific means, such as those described by Kanawaty (1979) and Salvendy (1992), to establish workloads for VDU operators, should be a high priority for every organization, since such methods set reasonable production standards or work output requirements, help to protect employees from excessive workloads, as well as help to ensure the quality of products.

The demand that is associated with the high levels of concentration required for computerized tasks can diminish the amount of social interaction during work, leading to social isolation of employees. To counter this effect, opportunities for socialization for employees not engaged in computerized tasks, and for employees who are on rest breaks, should be provided. Non-computerized tasks which do not require extensive concentration could be organized in such a way that employees can work in close proximity to one another and thus have the opportunity to talk among themselves. Such socialization provides social support, which is known to be an essential modifying factor in reducing adverse mental health effects and physical disorders such as cardiovascular diseases (House 1981). Socialization naturally also reduces social isolation and thus promotes improved mental health.

Since poor ergonomic conditions can also lead to psychosocial problems for VDU users, proper ergonomic conditions are an essential element of complete job design. This is covered in some detail in other articles in this chapter and elsewhere in the Encyclopaedia.

Finding Balance

Since there are no “perfect” jobs or “perfect” workplaces free from all psychosocial and ergonomic stressors, we must often compromise when making improvements at the workplace. Redesigning processes generally involves “trade-offs” between excellent working conditions and the need to have acceptable productivity. This requires us to think about how to achieve the best “balance” between positive benefits for employee health and productivity. Unfortunately, since so many factors can produce adverse psychosocial conditions that lead to stress, and since these factors are interrelated, modifications in one factor may not be beneficial if concomitant changes are not made in other related factors. In general, two aspects of balance should be addressed: the balance of the total system and compensatory balance.

System balance is based on the idea that a workplace or process or job is more than the sum of the individual components of the system. The interplay among the various components produces results that are greater (or less) than the sum of the individual parts and determines the potential for the system to produce positive results. Thus, job improvements must take account of and accommodate the entire work system. If an organization concentrates solely on the technological component of the system, there will be an imbalance because personal and psychosocial factors will have been neglected. The model given in figure 1 of the work system can be used to identify and understand the relationships between job demands, job design factors, and stress which must be balanced.

Since it is seldom possible to eliminate all psychosocial factors that cause stress, either because of financial considerations, or because it is impossible to change inherent aspects of job tasks, compensatory balance techniques are employed. Compensatory balance seeks to reduce psychological stress by changing aspects of work that can be altered in a positive direction to compensate for those aspects that cannot be changed. Five elements of the work system—physical loads, work cycles, job content, control, and socialization—function in concert to provide the resources for achieving individual and organizational goals through compensatory balance. While we have described some of the potential negative attributes of these elements in terms of job stress, each also has positive aspects that can counteract the negative influences. For instance, inadequate skill to use new technology can be offset by employee training. Low job content that creates repetition and boredom can be balanced by an organizational supervisory structure that promotes employee involvement and control over tasks, and job enlargement that introduces task variety. The social conditions of VDU work could be improved by balancing the loads that are potentially stressful and by considering all of the work elements and their potential for promoting or reducing stress. The organizational structure itself could be adapted to accommodate enriched jobs in order to provide support to the individual. Increased staffing levels, increasing the levels of shared responsibilities or increasing the financial resources put toward worker well-being are other possible solutions.

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