Testing the 3-factor model of occupational stress: the impact of demands, control and social support on a mail sorting task

This study tests a 3-factor model of occupational stress, which predicts that job demands, job control and social support influence levels of strain. In a laboratory simulation of mail sorting, task demands, control and social supports were manipulated systematically. Pre- and post-task measures of self reported stress and arousal were compared across groups. Performance was measured continuously during the computer task and all 120 participants reported their perceived performance afterwards. Stress was found to be higher and perceived performance was lower in conditions of high demand; this pattern was also observed in conditions of low social support. Contrary to the hypotheses put forward in this paper, task control did not affect stress and the manipulations did not interact to produce elevated stress. However, task performance was poorer in conditions of high demand and in conditions of low control, and there was a significant interaction between demand and control for performance. Work preference measures indicated that the level of fit between ideal and actual social support influenced stress and perceived performance.     

Impacts of buyers' order batching on the supplier's demand correlation and capacity utilization in a branching supply chain

There are several ways for a manufacturer to cope with demand uncertainty, e.g. inventories, capacity and cash. Among these, this study focuses on the second one, the capacity, especially on the problem of investing in flexible facilities and enhancing their utilization via demand management. In a supply chain, demands that an upstream firm (supplier) faces are the purchase orders from the downstream members (buyers). We analyse the impacts of buyers' order batching on the supplier's demand correlation and capacity utilization in a simple branching supply chain, where a supplier does business with two buyers whose market demands are correlated. Our results show that: (i) a supplier whofacesa smaller demand correlation coefficient (i.e. closer to-1) would invest more in flexible facilities; (ii) an increase in order lot size mitigates the correlation of purchase orders; and (iii) a supplier whose facilities are flexible would prefer frequent orders with smaller lots only when market demands are highly negatively correlated. This means that even suppliers whose facilities are flexible would rather prefer infrequent orders with larger lots in the presence of positively correlated demands. Additionally, some managerial implications are discussed.     

The importance of knowing the affective meaning of job demands revisited

This paper starts with the assumption that when people are asked to describe the level of demands they face at work, it cannot be assumed that those demands are necessarily stressful, even if they are rated as strong or high demands. Thirty demand questions were designed for use with a sample of 2,253 public sector employees in Western Australia. As well as rating frequency of demand the respondents were asked to rate their level of dissatisfaction with the demand. For only 16 of the demands was there a correlation high enough to assume that the demand might be a stressor. Having demonstrated this, the rest of the paper compares different ways of combining the two scores to predict the level of psychological distress as measured by the General Health Questionnaire (GHQ12). The results support the claim in the title, that it is important to know the affective meaning of job demands.     

The importance of knowing the affective meaning of job demands revisited

This paper starts with the assumption that when people are asked to describe the level of demands they face at work, it cannot be assumed that those demands are necessarily stressful, even if they are rated as strong or high demands. Thirty demand questions were designed for use with a sample of 2,253 public sector employees in Western Australia. As well as rating frequency of demand the respondents were asked to rate their level of dissatisfaction with the demand. For only 16 of the demands was there a correlation high enough to assume that the demand might be a stressor. Having demonstrated this, the rest of the paper compares different ways of combining the two scores to predict the level of psychological distress as measured by the General Health Questionnaire (GHQ12). The results support the claim in the title, that it is important to know the affective meaning of job demands.     

Self-control demands, cognitive control deficits, and burnout

Self-control involves inhibiting undesired behaviours and emotions, and it can be particularly relevant in the service sectors. Recent theoretical developments in cognitive and social psychology suggest that the demands on an individual of exercising self-control have an effect as a source of stress at work. In turn, burnout could be associated with being unable to meet those demands. It was expected that cognitive control deficits, as assessed by a questionnaire measure of self-reported failures in perception, memory, and action, would function as a vulnerability factor in the relationship between self-control demands and indicators of job strain. Data from 630 staff members of a German municipal administration revealed significant main effects of both self-control demands and cognitive control deficits on the burnout dimensions of emotional exhaustion and depersonalization. Both predictors were positively related to burnout. In addition, the results provided clear evidence of the vulnerability hypothesis of cognitive control deficits. By way of contrast, musculoskeletal complaints did not reflect similar main and interactive effects of self-control demands and cognitive control deficits. The requirements for self control in the service sector are expected to increase as the sector expands, and the practical implications for this are discussed.     

The New Zealand government approach to stress and fatigue

Abstract

Self-control involves inhibiting undesired behaviours and emotions, and it can be particularly relevant in the service sectors. Recent theoretical developments in cognitive and social psychology suggest that the demands on an individual of exercising self-control have an effect as a source of stress at work. In turn, burnout could be associated with being unable to meet those demands. It was expected that cognitive control deficits, as assessed by a questionnaire measure of self-reported failures in perception, memory, and action, would function as a vulnerability factor in the relationship between self-control demands and indicators of job strain. Data from 630 staff members of a German municipal administration revealed significant main effects of both self-control demands and cognitive control deficits on the burnout dimensions of emotional exhaustion and depersonalization. Both predictors were positively related to burnout. In addition, the results provided clear evidence of the vulnerability hypothesis of cognitive control deficits. By way of contrast, musculoskeletal complaints did not reflect similar main and interactive effects of self-control demands and cognitive control deficits. The requirements for self control in the service sector are expected to increase as the sector expands, and the practical implications for this are discussed.     

Helping people to sort it out: The role of social support in the Job Strain Model

This paper reports three studies of occupational stress investigating the role of social support as an intervening variable in the Job Strain Model (Karasek, 1979). A computer simulated mail-sorting work environment was used to assess the effect of demands, control and social support on measures of strain, satisfaction, and perceived and actual task performance. The first experiment ( N =60) tests the basic Job Strain Model by manipulating levels of task demand and control. The second experiment ( N =120) compares high and low levels of two types of social support (informational support and emotional support) to determine whether and how they interact with extreme conditions of the Job Strain Model (high strain and low strain). The final experiment ( N =90) investigates positive and negative forms of social support (praise and criticism) in relation to extreme job strain conditions. Results show that the job strain model is consistent with the stress and performance data, although stress showed no Demand ×Control interaction. Social supports increased arousal, satisfaction and perceived performance, but did not affect stress or task performance. Moreover, contrary to buffer theories, social supports did not interact with the job strain variables. Congruence between preferred and experienced emotional support levels also predicted performance.     

Service Completion Estimates for Cross‐trained Workforce Schedules under Uncertain Attendance and Demand

Although cross‐trained workers offer numerous operational advantages for extended‐hour service businesses, they must first be scheduled for duty. The outcome from those decisions, usually made a week or more in advance, varies with realized service demand, worker attendance, and the way available cross‐trained workers are deployed once the demands for service are known. By ignoring the joint variability of attendance and demand, we show that existing workforce scheduling models tend to overstate expected schedule performance and systematically undervalue the benefits of cross‐training. We propose a two‐stage stochastic program for profit‐oriented cross‐trained workforce scheduling and allocation decisions that is driven by service completion estimates obtained from the convolution of the employee attendance and service demand distributions. Those estimates, reflecting optimal worker allocation decisions over all plausible realizations of attendance and demand, provide the gradient information used to guide workforce scheduling decisions. Comparing the performance of workforce scheduling decisions for hundreds of different hypothetical service environments, we find that solutions based on convolution estimates are more profitable, favor proportionately more cross‐trained workers and fewer specialists, and tend to recommend significantly larger (smaller) staffing levels for services under high (low) contribution margins than workforce schedules developed with independent expectations of attendance and demand.     

The effects of new dimensions of psychological job demands and job control on active learning and occupational health

Recent changes in job content may have led to changes in job demands and control, and earlier operationalizations of the demand concept may be too general (MT). The aim of this paper is to show how new dimensions of psychological job demands are related to two sets of outcome variables, employee health and active learning, and how these relationships are modified or interact with social support and types of job control. The study was carried out as a survey among employees of 13 electric companies in Norway, N=2435. Lisrel was used to assess the fit of the proposed models. Compared to the traditional demands control model, an extended version used in this study increased the explained variance on an average by 4% on various occupational health variables. It was found that various dimensions of demands were differentially related to the outcome variables. Skill discretion uniformly reduced the effect of the demands: for groups low in skill discretion there was a stronger relationship between demands and outcomes than for groups high in skill discretion. The interaction pattern for the remaining control and support variables was however more complicated and warrants further study. The practical implications are that employers should carefully consider the quality of work. Special attention should be given to the quantitative demands of the jobs, since there seems to be few moderators for the relationship between those demands and job stress and subjective health complaints.     

Helping people to sort it out: The role of social support in the Job Strain Model

This paper reports three studies of occupational stress investigating the role of social support as an intervening variable in the Job Strain Model (Karasek, 1979). A computer simulated mail-sorting work environment was used to assess the effect of demands, control and social support on measures of strain, satisfaction, and perceived and actual task performance. The first experiment ( N =60) tests the basic Job Strain Model by manipulating levels of task demand and control. The second experiment ( N =120) compares high and low levels of two types of social support (informational support and emotional support) to determine whether and how they interact with extreme conditions of the Job Strain Model (high strain and low strain). The final experiment ( N =90) investigates positive and negative forms of social support (praise and criticism) in relation to extreme job strain conditions. Results show that the job strain model is consistent with the stress and performance data, although stress showed no Demand 2 Control interaction. Social supports increased arousal, satisfaction and perceived performance, but did not affect stress or task performance. Moreover, contrary to buffer theories, social supports did not interact with the job strain variables. Congruence between preferred and experienced emotional support levels also predicted performance.     

The effects of new dimensions of psychological job demands and job control on active learning and occupational health

Abstract

Recent changes in job content may have led to changes in job demands and control, and earlier operationalizations of the demand concept may be too general (MT). The aim of this paper is to show how new dimensions of psychological job demands are related to two sets of outcome variables, employee health and active learning, and how these relationships are modified or interact with social support and types of job control. The study was carried out as a survey among employees of 13 electric companies in Norway, N=2435. Lisrel was used to assess the fit of the proposed models. Compared to the traditional demands control model, an extended version used in this study increased the explained variance on an average by 4% on various occupational health variables. It was found that various dimensions of demands were differentially related to the outcome variables. Skill discretion uniformly reduced the effect of the demands: for groups low in skill discretion there was a stronger relationship between demands and outcomes than for groups high in skill discretion. The interaction pattern for the remaining control and support variables was however more complicated and warrants further study. The practical implications are that employers should carefully consider the quality of work. Special attention should be given to the quantitative demands of the jobs, since there seems to be few moderators for the relationship between those demands and job stress and subjective health complaints.     

Expatriate Managers,Product Relatedness,and IJV Performance: A Resource and Knowledge-based Perspective

Drawing from the resource and knowledge-based perspectives, we examine the role expatriates play as a critical managerial resource within the multinational's international joint-venture (IJV). By using a large sample (3772 IJV annual performance years) of Japanese IJVs in the USA from 1991 to 2001, we find that expatriate deployment shows a curvilinear (inverted-U) relationship with IJV performance. Further, this relationship is positively moderated by product relatedness between the parent and the IJV.     

Occupational stress and cardiovascular reactivity in blue-collar workers

This study analyses the influence of chronic occupational stress on cardiovascular reactivity (heart rate [HR] and blood pressure [BP] elevation from baseline to maximal challenge) during a standard mental stress test (modified version of the STROOP colour word interference test). The test was applied to a sample of 190 healthy male blue-collar workers at the end of a regular working day. Our research hypothesis was based on the assumption that sustained autonomic activation due to chronic occupational stress may reduce cardiovascular responsiveness to challenge: workers defined by high level of chronic occupational stress exhibited lower maximal HR and BP elevations under challenge as compared to workers with low levels of stress. Three distinct indicators of occupational stress were derived from structured interviews: 'cumulative workload', 'worsening of job conditions', and 'high demand and low job security'. Statistical analysis, using ANOVA, showed that all main effects of chronic stress were in the expected direction (6 of 9 effects were statistically significant at the 0'05 level). These effects remained stable after adjusting for age, hypertensive status, physiological baseline level, cigarette smoking, test performance, and individual style of coping. In summary, cardiovascular reactivity under experimental challenge is modulated by an individual's experience of chronic occupational stress.     

A Model for Partial Product Complementarity and Strategic Production Decisions under Demand Uncertainty

This paper considers a general industrial setting where multiple manufacturers each produce a different product and sell it to the markets. These products are partially complementary in the sense that there is a common demand stream that requests all these products as complementary sets and there are streams of individual demands each requesting only one of the products. All demands are uncertain and may follow any general, joint distributions. Facing demand uncertainties, the manufacturers each choose a production quantity for its product with an objective to maximize its own expected profit. We formulate the problem as a non‐cooperative game to study the strategic interactions of such firms and their implications to supply chain performance. We show that such a game may have numerous equilibria. Among all the possible equilibria, however, we prove that there always exists a unique one that maximizes each and every manufacturer's profit, and we derive an explicit solution for this Pareto‐optimal equilibrium point. We further study the optimal solution for a centralized system and compare it with the decentralized solution. Managerial insights are drawn as to how system parameters and control mechanisms affect firms' decisions and performance.     

The Job Demand-Control (-Support) Model and psychological well-being: A review of 20 years of empirical research

The Job Demand-Control (JDC) model (Karasek, 1979) and the Job Demand-Control-Support (JDCS) model (Johnson, and Hall, 1988) have dominated research on occupational stress in the last 20 years. This detailed narrative review focuses on the JDC(S) model in relation to psychological well-being. It covers research from 63 samples, published in the period 1979-1997. In the review a distinction is drawn between two different hypotheses prevailing in research on the models. According to the strain hypothesis of the JDC model, employees working in a high-strain job (high demands-low control) experience the lowest well-being. The buffer hypothesis states that control can moderate the negative effects of high demands on well-being. Translating these hypotheses to the expanded JDCS model, the iso-strain hypothesis predicts the most negative outcomes among workers in an iso-strain job (high demands-low control-low social support/isolation), whereas the buffer hypothesis states that social support can moderate the negative impact of high strain on well-being. Although the literature gives considerable support for the strain and iso-strain hypotheses, support for the moderating influence of job control and social support is less consistent. The conceptualization of demands and control is a key factor in discriminating supportive from nonsupportive studies. Only aspects of job control that correspond to the specific demands of a given job moderate the impact of high demands on well-being. Furthermore, certain subpopulations appear to be more vulnerable to high (iso)strain, whereas others benefit more from high control. On the basis of the results of this review, suggestions for future research and theoretical development are formulated.     

The Job Demand-Control (-Support) Model and psychological well-being: a review of 20 years of empirical research

The Job Demand-Control (JDC) model (Karasek, 1979) and the Job Demand-Control-Support (JDCS) model (Johnson, and Hall, 1988) have dominated research on occupational stress in the last 20 years. This detailed narrative review focuses on the JDC(S) model in relation to psychological well-being. It covers research from 63 samples, published in the period 1979-1997. In the review a distinction is drawn between two different hypotheses prevailing in research on the models. According to the strain hypothesis of the JDC model, employees working in a high-strain job (high demands-low control) experience the lowest well-being. The buffer hypothesis states that control can moderate the negative effects of high demands on well-being. Translating these hypotheses to the expanded JDCS model, the iso-strain hypothesis predicts the most negative outcomes among workers in an iso-strain job (high demands-low control-low social support/isolation), whereas the buffer hypothesis states that social support can moderate the negative impact of high strain on well-being. Although the literature gives considerable support for the strain and iso-strain hypotheses, support for the moderating influence of job control and social support is less consistent. The conceptualization of demands and control is a key factor in discriminating supportive from nonsupportive studies. Only aspects of job control that correspond to the specific demands of a given job moderate the impact of high demands on well-being. Furthermore, certain subpopulations appear to be more vulnerable to high (iso)strain, whereas others benefit more from high control. On the basis of the results of this review, suggestions for future research and theoretical development are formulated.     

动态车辆路径问题排队模型分析

分析了一类动态车辆路径问题,其中顾客需求以泊松流形式出现,现场服务时间服从一般分布.提出解决该问题的两种策略:顺序服务策略和中点改进策略,利用排队论、几何概率论等领域的知识分别求出了这两种策略的系统时间,并通过仿真数据实验验证了这两种策略的有效性.     

Supporting Quick Response Through Scheduling of Make-to-Stock Production/Inventory Systems*

Scheduling of traditional job shops in make-to-order systems has seen extensive research over the past three decades. In such systems, performance is often related to various job completion metrics such as average flow time, average lateness, etc. This paper examines a scheduling problem in a make-to-stock environment where individual job completion measures are irrelevant. In this case, customer orders are satisfied through on-hand inventory where customer service is more closely related to the manufacturer's ability to quickly satisfy demand. We consider the role of scheduling in reducing inventories and improving customer service in the context of a manufacturer who assembles several different products on a single assembly line. We develop scheduling rules for such a system and experimentally compare their performance to those typically used in such environments. Our results indicate that rules which consider the inventory position and demand forecast outperform traditional fixed cycle rules.     

Stress,coping and problem solving

Abstract

This paper outlines the developing consensus on the nature of stress. It offers a definition of stress as a psychological state derived from the person's appraisal of their ability to cope with the demands which are made of them. The paper then examines the concept of coping and explores its role in stress theory. It contrasts two different approaches to the study of coping: the classification of coping strategies, and the investigation of the process of coping—coping as ‘problem solving’. The paper focuses on the latter and in doing so it describes the nature of rational models of problem solving, considering their utility and application to stress management.     

Burnout and impaired cognitive functioning: The role of executive control in the performance of cognitive tasks

Abstract

Burnout patients often report deficits in cognitive control, and there is a need to understand the processes involved. Drawing on recent findings, we hypothesized that emotional exhaustion and task-related demands on executive control would interact in predicting performance in tasks requiring the updating and monitoring of working memory as well as the inhibition of prepotent (dominant or automatic) responses. In accordance with recent conceptualizations of burnout, we focused on emotional exhaustion as the core symptom of burnout. The sample comprised 81 employees recruited from nursing homes for elderly care in Germany, who participated in a laboratory study involving cognitive tasks. Based on a median split, participants were divided into two groups: those with high burnout and those with low burnout. In line with our hypotheses, the high exhaustion participants performed less well than those with low exhaustion only when tasks put high demands on their executive control. As predicted, high levels of emotional exhaustion were associated with more errors and longer reaction times when demands on executive control were high, whereas no performance differences were found when both tasks put low demands on executive control. The implications for practice are discussed.