12-h workdays: current knowledge and future directions

Work schedules other than those based on the traditional 8-h workday duration have become much more common in recent years. Many such schedules compress the work week into three or four longer workdays and include an increased number of days off. In particular, rosters based on 12-h workdays have gained in popularity, and such rosters have been the focus of considerable research. The literature on 12-h workdays is, however, full of inconsistencies. Not surprisingly, there is considerable evidence from some of these studies that 12-h shifts tend to cause more fatigue than 8-h shifts. This extra fatigue may be associated with lower work efficiency, and with more errors and accidents. There is also strong evidence that workers prefer 12-h shifts due to some perceived advantages. The present paper reviews and examines these studies and their findings and discusses some possible reasons for the apparent contradictions in reported findings. Directions for decision makers and future research are suggested.     

Attitudes of nurses towards 8-h and 12-h shift systems

Twelve-hour shift schedules are becoming increasingly popular. The present study was designed to investigate the attitudes of nurses, their priorities with respect to working time and other aspects of the working conditions, and to analyse the conditions leading to a diminished satisfaction with the shift schedule and to aspirations for a change of schedule. Questionnaires were returned by 880 nurses (78% return rate) from 12 hospitals. A total of 65% worked 12-h shifts and 35% worked 8-h shifts. A considerable proportion of both groups showed a low satisfaction with their schedule and a desire to change the schedule (44% of those working 12-h shifts, 47% of those working 8-h shifts). Concerning effects of the shift schedule on work strain, continuity of service, health, family and leisure time, 8-h shifts were rated more favourably, especially by those working these shifts, but also by nurses working 12-h systems, with the exception of effects on leisure time and to some extent also on continuity of service and on family. Effects of the shift schedule on social responsibilities and leisure time activities turned out to be a major moderating variable in both groups with respect to schedule satisfaction and attitudes towards a change of schedule. Apparently neither type of shift system, traditional 12-h shift rosters or rotating 8-h shifts, is very appealing to the nurses. A stronger relationship between social consequences and health state in nurses working 12-h shifts indicates that in this group negative effects on family and leisure time might be due to an increased need for recuperation, which reduces effective leisure time.     

Attitudes of nurses towards 8-h and 12-h shift systems

Abstract

Twelve-hour shift schedules are becoming increasingly popular. The present study was designed to investigate the attitudes of nurses, their priorities with respect to working time and other aspects of the working conditions, and to analyse the conditions leading to a diminished satisfaction with the shift schedule and to aspirations for a change of schedule. Questionnaires were returned by 880 nurses (78% return rate) from 12 hospitals. A total of 65% worked 12-h shifts and 35% worked 8-h shifts. A considerable proportion of both groups showed a low satisfaction with their schedule and a desire to change the schedule (44% of those working 12-h shifts, 47% of those working 8-h shifts). Concerning effects of the shift schedule on work strain, continuity of service, health, family and leisure time, 8-h shifts were rated more favourably, especially by those working these shifts, but also by nurses working 12-h systems, with the exception of effects on leisure time and to some extent also on continuity of service and on family. Effects of the shift schedule on social responsibilities and leisure time activities turned out to be a major moderating variable in both groups with respect to schedule satisfaction and attitudes towards a change of schedule. Apparently neither type of shift system, traditional 12-h shift rosters or rotating 8-h shifts, is very appealing to the nurses. A stronger relationship between social consequences and health state in nurses working 12-h shifts indicates that in this group negative effects on family and leisure time might be due to an increased need for recuperation, which reduces effective leisure time.     

Health, well-being and burnout of ICU nurses on 12- and 8-h shifts

It is generally agreed that some features of shift systems can influence the extent of well-being and health problems experienced by the workers involved. Extended working days (9-12 h) have been found to aggravate some problems associated with shiftwork, especially when the work is mentally and emotionally demanding. The aim of the study was to compare measures of health, sleep, psychological and social well-being, job satisfaction and burnout of ICU nurses on 12- and 8-h shifts. The groups of subjects were matced for age, length of shiftwork experience, marital status and number of hours worked. the 12-h shift nurses, when compared to their 8-h shift colleagues, experienced more chronic fatigue, cognitive anxiety, sleep disturbance and emotional exhaustion. Job satisfaction seems to be independent of the shift duration. The nurses on 12-h shifts reported less social and domestic disruption than those on 8-h shifts. The 12-h shift nurses showed worse indices of health, well-being and burnout tan the 8-h shift nurses. It is suggested that this may be associated with their longer daily exposure to the stress of work. The increased number of rest days of 12-h shift nurses seems tobe insufficient to dissipate the adverse health and well-being effects that built up over their longer shifts.     

Ten-hour days and eight-hour nights: Can the Ottawa Shift System reduce the problems of shiftwork?

Most research on condensed working weeks has concentrated either on daywork only or on 12-h shifts. The Police Force in Ottawa, Canada, have been reporting positive experiences with a shift system which retains an 8-h night shift but which extends the day shifts to 10-h, thus enabling a 6-day rest period following night shifts. In the present study, the effects on well-being, personal, social and work disruption, alertness and sleep were evaluated when the same system was adopted by a police force in the UK. A survey was conducted at four police stations prior to the change and again 6 months after the change. Two of the stations did not change to the Ottawa system and hence formed a control group. The stations originally worked 8-h shifts with blocks of seven consecutive shifts. The results suggest that, in contrast to the control group the 'Ottawa' group experienced a significant improvement in well-being, a significant reduction in personal, social and work disruption, and a significant increase in average sleep duration over a shift cycle. Self-rated alertness at the end of shifts was no worse under the Ottawa system. However, the values were still very low at the end of the night shift and, with an average sleep duration between night shifts of only 6-4-h it suggests that the block of seven nights in the Ottawa system may need review.     

Demanding work schedules and mental health in nursing assistants working in nursing homes

Nursing home assistants have physically and emotionally challenging jobs, and they often work demanding schedules in order to provide 24-h care. While the physical effects of demanding work schedules have been studied, little is known about the impact on mental health. This study explored the relationship between demanding scheduling variables and mental health indicators of depression, anxiety and somatization. A cross-section of 473 US female nursing assistants working in nursing homes was surveyed. Work schedule characteristics included shiftwork, hours per day and week, days per week, number of weekends per month, number of double shifts per month, breaks, and number of jobs worked. Working two or more double-shifts per month was associated with increased risk for all mental health indicators, and working 6-7 days per week was associated with depression and somatization. There was a trend for increasing odds of adverse mental health with increased numbers of demanding work schedule factors. The odds of depression was increased four-fold when working 50+ h/week, more than two weekends/month and more than two double shifts/month. Providing work schedules that are less unhealthy may have implications for both worker retention and the quality of care delivered to nursing home residents.     

Demanding work schedules and mental health in nursing assistants working in nursing homes

Nursing home assistants have physically and emotionally challenging jobs, and they often work demanding schedules in order to provide 24-h care. While the physical effects of demanding work schedules have been studied, little is known about the impact on mental health. This study explored the relationship between demanding scheduling variables and mental health indicators of depression, anxiety and somatization. A cross-section of 473 US female nursing assistants working in nursing homes was surveyed. Work schedule characteristics included shiftwork, hours per day and week, days per week, number of weekends per month, number of double shifts per month, breaks, and number of jobs worked. Working two or more double-shifts per month was associated with increased risk for all mental health indicators, and working 6–7 days per week was associated with depression and somatization. There was a trend for increasing odds of adverse mental health with increased numbers of demanding work schedule factors. The odds of depression was increased four-fold when working 50+ h/week, more than two weekends/month and more than two double shifts/month. Providing work schedules that are less unhealthy may have implications for both worker retention and the quality of care delivered to nursing home residents.     

Psychophysiological coherence training to moderate air traffic controllers’ fatigue on rotating roster

The nature of the current rotating roster, providing 24-h air traffic services over five irregular shifts, leads to accumulated fatigue which impairs air traffic controllers’ cognitive function and task performance. It is imperative to develop an effective fatigue risk management system to improve aviation safety based upon scientific approaches. Two empirical studies were conducted to address this issue. Study 1 investigated the mixed effect of circadian rhythm disorders and resource depletion on controllers’ accumulated fatigue. Then, study 2 proposed a potential biofeedback solution of quick coherence technique which can mitigate air traffic controllers’ (ATCOs’) fatigue while on controller working position and improve ATCOs’ mental/physical health. The current two-studies demonstrated a scientific approach to fatigue analysis and fatigue risk mitigation in the air traffic services domain. This research offers insights into the fluctuation of ATCO fatigue levels and the influence of a numbers of factors related to circadian rhythm and resource depletion impact on fatigue levels on study 1; and provides psychophysiological coherence training to increase ATCOs’ fatigue resilience to mitigate negative impacts of fatigue on study 2. Based on these two studies, the authors recommended that an extra short break for air traffic controllers to permit practicing the quick coherence breathing technique for 5 min at the sixth working hour could substantially recharge cognitive resources and increase fatigue resilience. Application: Present studies highlight an effective fatigue intervention based on objective biofeedback to moderate controllers’ accumulated fatigue as a result of rotating shift work. Accordingly, air navigation services providers and regulators can develop fatigue risk management systems based on scientific approaches to improve aviation safety and air traffic controller's wellbeing.     

Dealing with shift work: Physical fitness, temperature, and napping

This paper reviews the effects of generally controllable factors such as physical conditioning, ambient temperature, and amount of prior sleep in adjustment to night work periods and shift work. One can expect a 5-10% decline in capacity for work in nocturnal work periods as compared to daytime work periods. This decreased capacity would dissipate if workers maintained a consistent sleep-wake routine for 8-16 days after moving to a new shift. Proven means for accelerating this adaptation are currently not available. The ability to perform work also declines as the length of the work period increases but depending upon individual tasks. Physical conditioning improves mood and general well-being, but no strong evidence currently indicates that conditioning increases tolerance or adjustment to shift work.

Increased ambient temperature increases the stress of work, although studies do not address heat as a factor in adjustment to shift work. While lower nocturnal temperature would be assumed to reduce heat stress during night shifts, supporting data does not exist. Studies have not addressed the negative consequences of cold stress or of rotating from night to day shifts with added heat stress.

The proper use of short sleep periods either as preparation for or as a response to a shift change can ameliorate some effects of shift rotation. Data indicate that performance on 'graveyard' shifts can be maintained close to baseline levels following true prophylactic naps while performance may decline by up to 30% when such naps are not taken. While there is evidence that naps or even rest periods without sleep are beneficial in improving mood in normal young adults, these data do not apply to 'replacement' naps. Studies of interjected naps imply that such naps do reduce sleep debt but do not imply that such naps are more beneficial than longer sleep periods. Naps appear to be most advantageous when the accumulated sleep debt is least.     

HRM Practices and Employee Commitment: Possibilities, Pitfalls and Paradoxes

Much recent writing on Human Resources Management (HRM) has emphasized the desirability of a committed workforce and the central role of HRM practices in establishing and maintaining such commitment. Little empirical evidence for such effects has been presented however, and the conceptualization of employee commitment has often been confused, failing to recognize its multi–dimensional nature. Researchers have sought to identify the antecedents of commitment, concentrating on personal/demographic, task, role and supervisory style variables taken from job satisfaction research. With regard to organizational and career commitment, it may be more fruitful to examine the impact of HRM policies and practices. Several studies undertaken by the authors demonstrating the impact on employee commitment of such HRM practices as selection, assessment, induction and training are reviewed, indicating the possibilities for research and practice in this area. Such studies also reveal some pitfalls in the over–simple, uncritical models of commitment often presented, and some paradoxical findings from the authors' own work are used to present a more adequate perspective on the commitment process.     

The compressed work week as organizational change: behavioral and attitudinal outcomes

The results from recent studies on the compressed work week have been compiled and categorized in order to provide some basis for generalizing the effects of the work schedule on employee attitudes and behavior. It appears that attitudes toward the compressed week are favorable, with some generalization to job attitudes. Performance outcomes are ambiguous, although there are no reported decreases; fatigue seems to be the only negative aspect of the longer day. An examination of mediating variables suggests more complex relationships between the implementation of the compressed work week and potential outcomes. These relationships are described and directions are indicated for future research.     

New perspectives on board research: changing the research agenda

Scholars and practitioners have recently devoted considerable attention to boards of directors, but far more research is needed. We still know little about how boards actually work and how their behavior may be improved to contribute to value creation. During more than two decades agency theory has been the dominant theory in studies about boards of directors. When relaxing some of the assumptions in agency theory several new pathways for new research arise. To present new perspectives on board research we follow in this essay some of the pathways arising from relaxing agency theory assumptions about complete contracts. Alternative theoretical approaches, research questions and methods are suggested.     

Diversification and Performance in Developed and Emerging Market Contexts: A Review of the Literature*

The link between diversification and performance has become an important topic for research in diverse fields such as strategic management, industrial organization and financial management. However, a synthesis of the research done in developed and emerging markets is missing. This paper attempts such a synthesis by comparing and contrasting the past cumulative empirical research evidence on the relationship between diversification and firm performance in the context of developed economies to the more recent work in the emerging economies. The empirical literature has been divided into three broad perspectives, and the paper highlights the considerable diversity in its findings in developed and emerging markets across each of these perspectives. Based on this study, it is proposed that related diversification is preferable in developed economies and should be based on specific resources, whereas unrelated diversification is appropriate in emerging economies and should be based on generic resources. Although agency problems exist in both contexts, it is argued that the type of problem differs in developed and emerging markets. The paper concludes by identifying three directions for future research. First, the relationship between diversification and performance should be examined across each industry separately and not in aggregate. Secondly, future research needs to examine the organizational mechanisms required to make diversification successful. Finally, the relationship needs to be examined under unstable and dynamic situations such as the current global economic downturn.     

Use of robust estimators of missing data in evaluating shiftwork performance

Abstract

Major problems apparent in studies evaluating the performance of employees across a large number of shifts often involve data missing due to a lack of employee participation in all possible shifts, and large variance around central tendency estimators owing to extreme responses on performance measures. These problems and possible solutions are considered here with reference to a data set collected from a number of shiftworkers in the steel industry. Data were collected from 28 employees over a morning shift and night-shift roster. The shift consisted of two cycles of MORNING-MORNING-NIGHT-NIGHT. The employees were male computer operators working a 12-h shift. The work required them to be constantly alert, and to read, monitor and respond to messages from multiple media channels. Included in the test battery were five performance indicators of cognitive speed and power. This battery was delivered using two IBM computers, which controlled the sequences and administration of the cognitive tasks. Administration of the battery was conducted in the work room and undertaken as close as possible to starting work, and as close as possible to completing work. The findings indicate that regression modelling was the most efficient way of estimating missing data. The use of M-estimators reduced the influence of extreme values on parameter estimation, and increased effect size over that observed using raw data.     

Work system design and the quality of working life

Those responsible for designing work systems have considerable influence over the quality of working life of those employed both in operating and managing the system. Whilst research evidence is available regarding the impact of changes to jobs and work organisation, this research has tended to be based on changes made for remedial reasons where existing arrangements have been seen as the source of problems such as high labour turnover, low productivity, etc. The changes reported have often been limited in extent since assumptions regarding aspects such as the operations technology remain unchallenged. Those responsible for the initial design of work systems, however, have an opportunity to consider means for developing a “fit” between the needs of employees and the objectives of the organisation throughout the design process. Here we shall consider those aspects of work systems which relate particularly to the motivation of employees. Two situations are described, and contrasted, where those responsible for the design of the work systems place emphasis upon integrating the needs of individual employees into the initial design.     

Compensation for inconvenience: The utility of shift systems

Abstract

This study is part of a larger study airned at the development of a system for quantifying the inconvenience of shift schedules and schedule characteristics. The results can be used to reduce inconvenience (counter-value compensation) and to compute the monetary (counter-weight) compensability of shift schedules. The results presented here show that consensus exists among subjects from different organizations and with different background characteristics on the utility of several features, e.g. working at inconvenient hours, the irregularity of a schedule, and working during the evening (which has a positive value). The opinions slightly differ with respect to some other characteristics, such as very long shifts, work during the weekend and the average sequence length. The differences are possibly due to job characteristics.     

The impact of rest breaks upon accident risk,fatigue and performance: A review

This review's primary objective is to identify research examining the impact of rest breaks uponaccident risk in industrial settings. In the absence of much directly relevant research, the focus isbroadened to consider the impact of rest breaks upon performance and fatige, as well asepidemioogical evidence, in both transport and non-transport settings. Relevant studies are identifiedfrom a range of electronic sources. In general, regular rest breaks can be an effective means ofmaintaining performance, managing fatigue and controlling the accumulation of risk over prolongedtask perfonmance. While two-hourly breaks are common in many industrial settings, the scheduling ofadditional micro-breaks can be beneficial under at least some circumstances. While some evidencesupports allowing workers to take rest breaks that coincide with periods of heightened fatigue,workers sometims fail to take adequate breaks when they are needed. There is little hard evidenceconcerning the optimun length of rest breaks (other than for heavy physical work), or to support thecontention that increased rest-breaks can off-set the negative inpact of extending shift durations, or tosuggest that rest breaks counteract the neptive impacts of circadian variations in alertness, unless theyinvolve taking a nap or caffeine. The scarcity of epidemiological evidence in this area highlights theneed for more research.     

Work and rest in the long-distance road transport industry in Australia

To date management of fatigue in professional drivers has largely focused on strategies that limit the amount of time spent on the job. These approaches have, however, not taken into account the well-documented effect of time of day. Consequently, the likely impact of the pattern and timing of work and rest has received little attention. The results revealed that the group of drivers who did the shortest trips and worked the shortest weekly hours were the lowest reporters of fatigue, although longer hours were not always associated with the highest reporting of fatigue. In contrast, the shortest working hours were associated with earliest onset of fatigue. For all drivers, the influence of circadian rhythms was evident in the occurrence of fatigue, with better management of the problem evident among drivers who were able to arrange the timing of rest to more closely coincide with periods of fatigue. Thus, time of day appeared to be a more important influence in determining effective rest than did period of work. These findings raise questions about the validity of the assumption underlying work hour regulations for long-distance drivers which, currently, are universally based on duration of work.     

Voluntary Work‐related Technology Use during Non‐work Time: A Narrative Synthesis of Empirical Research and Research Agenda

The Internet and mobilization of information and communication technologies (ICTs) have made non‐manual work increasingly portable and remotely accessible. As a result, a considerable number of employees use their ICTs to engage in work‐related tasks during designated non‐work time, even without contractual obligation. However, existing research on such voluntary work‐related ICT use remains fragmented and spread across disciplines. The authors conducted a narrative review of 56 studies to identify themes in existing research, synthesize the evidence base and identify gaps in understanding. They identify five themes: (1) Social‐normative organizational context, (2) Job‐related characteristics and work processes, (3) Person characteristics, (4) Designated non‐work time and well‐being, and (5) Empowerment/Enslavement Paradox. A conceptual model of voluntary ICT use is developed by integrating the identified themes with existing organizational research, outlining the relationships between the identified themes and voluntary ICT use. The discussion emphasizes the need for more conceptual clarity on voluntary ICT use and related constructs, and for the integration of different disciplines and methodological approaches to advance knowledge in the field. The authors further identify person‐centred research as a critical future avenue to explore different ICT user types. Additionally, more research into the mechanisms and moderating influences regarding voluntary ICT use and its outcomes is considered advisable to advance knowledge on the Empowerment/Enslavement Paradox and its potential resolution. The paper concludes with preliminary implications to inform practice, addressing the need for employers to provide control over voluntary ICT use and employees enacting this control.     

Circadian rhythms and bright light: Recommendations for shift work

This paper starts with a brief review of the basic principles of human circadian rhythms relevant to understanding the problem of shift work. It then presents a more detailed critical review of the recent bright light literature, with an emphasis on methodological shortcomings, alternative interpretations, and areas that need further research. Evidence is presented which suggests that either a light-dark cycle (which includes bright light) or a sleep-wake schedule can act as a zeitgeber for human circadian rhythms. Current human phase response curves to bright light are reviewed. Light-work-sleep schedules are presented which have been designed to eliminate the physiologically based harmful consequences of shift work. These schedules include both bright light and sleep-wake schedule zeitgebers. Other practical applications of bright light treatment are mentioned.