Back to basics: Re-examination of Demand-Control Theory of occupational stress

The Demand-Control model of occupational stress posits an interaction between job demands and job control predicting psychological strain, but previous research has found such an interaction only rarely or inconsistently. Such research, however, has often failed to measure either demands or strain faithfully to the model's constructs, or has simply failed to test for a statistical interaction. The present study corrected these shortcomings by going back to basics. Using a sample of 115 employees in a manufacturing company, it operationalized the variables more consistently with their original conceptualizations. However, when the hypothesized Demand-Control interaction was then tested, it still failed. Outcomes other than psychological strain (e.g. job dissatisfaction) were related negatively rather than positively to demands. This highlights the difference between psychological strain and dissatisfaction and casts doubt on models positing dissatisfaction as an intervening variable between stressors and strains.     

The importance of context specificity in work stress research: A test of the Demand-Control-Support model in academics

Abstract

The Demand-Control (D-C) (Karasek, 1979) and the Demand-Control-Support (D-C-S) (Johnson & Hall, 1988; Johnson, Hall, & Theorell, 1989; Karasek & Theorell, 1990) models of work stress suggest that jobs with high demands and low control (and low support) are stressful. In line with the support in the literature for context-specificity in occupational stress research (Sparks & Cooper, 1999) and the limited and even contradictory support for interaction effects, the main aim of the present study was to examine how the D-C-S model applied in a well-defined occupational group. Using hierarchical regression analyses, and controlling for negative affect, the D-C-S model accounted for 26%, 6%, and 8% of the variance in job satisfaction, psychological distress and burnout, respectively, among 166 academics in a UK university. No two-way or three-way interactive effects were evident, but additive effects of job demands and control on psychological well-being and of job demands and support on both burnout and job satisfaction were shown, corroborating research showing that high job strain is linked to ill health and job dissatisfaction in this homogenous occupational sample. It is recommended that, in future, research includes more variables that are specific to a particular occupation.     

The importance of context specificity in work stress research: A test of the Demand-Control-Support model in academics

The Demand-Control (D-C) (Karasek, 1979) and the Demand-Control-Support (D-C-S) (Johnson & Hall, 1988; Johnson, Hall, & Theorell, 1989; Karasek & Theorell, 1990) models of work stress suggest that jobs with high demands and low control (and low support) are stressful. In line with the support in the literature for context-specificity in occupational stress research (Sparks & Cooper, 1999) and the limited and even contradictory support for interaction effects, the main aim of the present study was to examine how the D-C-S model applied in a well-defined occupational group. Using hierarchical regression analyses, and controlling for negative affect, the D-C-S model accounted for 26%, 6%, and 8% of the variance in job satisfaction, psychological distress and burnout, respectively, among 166 academics in a UK university. No two-way or three-way interactive effects were evident, but additive effects of job demands and control on psychological well-being and of job demands and support on both burnout and job satisfaction were shown, corroborating research showing that high job strain is linked to ill health and job dissatisfaction in this homogenous occupational sample. It is recommended that, in future, research includes more variables that are specific to a particular occupation.     

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 impact of sense of coherence and high-demand/low-control job environment on self-reported health,burnout and psychophysiological stress indicators

Sense of Coherence (SOC) is a new concept belonging to a salutogenic paradigm, proposing to explain health as contrasted to disease, a pathogenic paradigm. The Job Demand-Control (JDC) model of job stress suggests that the combination of high job demands and low job control, defined as job strain, is strongly associated with adverse health consequences. The aim of this study was to evaluate the relationship between SOC and the JDC model in assessment of negative job effects within three pathogenically defined contexts: self-reported health, burnout and psychophysiological stress indicators, assessing the explanatory value of SOC for such variables. The study was conducted with 103 employees of social-welfare and social-insurance agencies in Sweden. A questionnaire related to job conditions, health and burnout was administered, and blood samples were collected and analysed for serum concentrations of cortisol, prolactin and immunoglobulin G. Multiple-regression models were calculated including variables from all three contexts. In the analyses, a distinction was made between emotional job strain and quantitative job strain. The SOC interacted with emotional job strain, but the interaction also increased the independent effect of emotional job strain. The independent effect of SOC disappeared in most models when interaction was included. It is concluded that studies of job strain-effects according to the JDC model should include the SOC as an interaction factor.     

Job demands and work-related psychological responses among Malaysian technical workers: The moderating effects of self-efficacy

Abstract

Job design has long been found to affect the work-related psychological responses of employees, such as psychological strain, job satisfaction, and turnover intentions, but scholars have begun to question whether established theoretical relations regarding job design continue to hold given the enormous changes in the nature of work during the past two decades. It is also increasingly recognized that individual differences affect work behaviours in substantial ways, but few studies on work design have investigated these differences. We addressed these concerns with a two-wave longitudinal study among 245 technical workers at a telecommunications company in Malaysia, a country that has a collectivist culture and a high power distance between managers and subordinates. We examined the moderating effects of job control and self-efficacy on the relationships between job demands and employee responses. The results failed to support the job demands-control model, as job control variables did not moderate the impact of demands on employee work-related psychological responses. However, self-efficacy moderated their impact on psychological strain (although not on job satisfaction or turnover intentions). Our findings provide insight into the moderating effect of self-efficacy, and suggest that practitioners interested in reducing psychological strain should consider making efforts to increase self-efficacy among employees.     

The Demands-Control-Support model,locus of control and job dissatisfaction: A longitudinal study

The Job-Demands-Control model (Karasek, 1979) has been widely studied in the job stress field, but the results obtained are frequently contradictory. Therefore, some investigations have expanded the model by including social support and personality characteristics such as locus of control. However, results obtained with these elaborated models have not been conclusive either. The present study sets out to integrate both types of expansions by simultaneously including social support at work and the employee's locus of control in a longitudinal multi-national study among 542 administrative personnel from Belgium, England, Spain, Italy and Israel. Hierarchical moderated multiple regression showed a significant 4-way interaction term (Demands 2 Control 2 Social support 2 Locus of control) on the change in job dissatisfaction. This effect is qualified by the interaction between job demands and control only for an internal locus of control with high social support. Contrary to the prediction of the JDC model, which posits that high control has a buffering effect on job dissatisfaction, the study result indicates a damaging effect of excess control (perceived job control and high internal locus of control), specifically in high social support situations.     

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.     

Role clarity,work overload and organizational support: Multilevel evidence of the importance of support

The present study extended the demands-control-support model used in occupational stress research in two ways. First, it hypothesized that role clarity (i.e. role ambiguity), like control, would moderate the relationship between demands and psychological strain. Second, the study assessed support (from leaders) as a macro characteristic of the work-group environment. Data were drawn from a large study of US army soldiers, the study sample consisting of 1786 lower enlisted male soldiers. The inclusion of support as a work-group characteristic lead to a multilevel test of the model. A three-way multilevel interaction among work demands, role clarity and support was observed. As predicted, the relationship between demands and psychological strain was moderated by role clarity; however, this moderating relationship was found only when work-group support was high.     

Testing the demand-control-support model among health-care professionals: A structural equation model

Abstract

This paper reports a further empirical validation of the Demand-Control-Support Model (DCS model), which was developed by Johnson and colleagues (1988, 1989). Data were collected from a heterogeneous group of health-care professionals (nurses and nurses' aides; n = 249). Three major refinements were made to the validation of the DCS Model. First, all relationships in the model were estimated simultaneously by means of covariance structure modelling (LISREL 8). Second, the control dimension was refined substantially, using a psychometrically more sound assessment of the workers' autonomy. Third, the model was applied to the work of health-care professionals. The data did not confirm the assumption that both job strain and motivation are multiplicative functions of job demands, autonomy and social support. First, the results suggested that high levels of autonomy attenuate the increase of emotional exhaustion due to job demands. These results partially supported Karasek's Job Demand-Control Model (Karasek 1979). Second, high levels of social support proved to attenuate the increase of emotional exhaustion due to autonomy. Finally, the main effect of autonomy on job challenge implied that an increase in autonomy is accompanied by an increase in job challenge (and, consequently, job involvement). In addition, low job demands and a high amount of work-related support seem to reduce feelings of exhaustion and, consequently, health complaints.     

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 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.     

The impact of sense of coherence and high-demand/low-control job environment on self-reported health, burnout and psychophysiological stress indicators

Sense of Coherence (SOC) is a new concept belonging to a salutogenic paradigm, proposing to explain health as contrasted to disease, a pathogenic paradigm. The Job Demand-Control (JDC) model of job stress suggests that the combination of high job demands and low job control, defined as job strain, is strongly associated with adverse health consequences. The aim of this study was to evaluate the relationship between SOC and the JDC model in assessment of negative job effects within three pathogenically defined contexts: self-reported health, burnout and psychophysiological stress indicators, assessing the explanatory value of SOC for such variables. The study was conducted with 103 employees of social-welfare and social-insurance agencies in Sweden. A questionnaire related to job conditions, health and burnout was administered, and blood samples were collected and analysed for serum concentrations of cortisol, prolactin and immunoglobulin G. Multiple-regression models were calculated including variables from all three contexts. In the analyses, a distinction was made between emotional job strain and quantitative job strain. The SOC interacted with emotional job strain, but the interaction also increased the independent effect of emotional job strain. The independent effect of SOC disappeared in most models when interaction was included. It is concluded that studies of job strain-effects according to the JDC model should include the SOC as an interaction factor.     

The association between job skill discretion,decision authority and burnout

This paper reports on the relationship between dimensions of control (skill discretion and decision authority) and burnout (emotional exhaustion, depersonalization, and reduced personal accomplishment) among 164 human service workers. It examines the differential influence of job demands, control (skill discretion and decision authority) and social support (supervisor, co-workers, others) on each burnout dimension. Then it examines the moderating effects of higher skill discretion, higher decision authority, and higher social support on burnout. Low skill discretion was found to be associated with high emotional exhaustion and depersonalization and low personal accomplishment. The effects of decision authority were not statistically significant. High job demands were associated with high emotional exhaustion only. Social support (supervisor, co-worker, and others) was not associated with burnout when demographic variables and job characteristics were controlled for. Neither dimension of control moderated the impact of high job demands on burnout. Social support did not moderate the impact of high demands, low skill discretion, or low decision authority on any burnout dimension. The full model explained 44% of the variance in emotional exhaustion, 25% in depersonalization, and 42% in personal accomplishment. Despite its limitations, the study suggests that the Job Demand-Control model may provide a useful theoretical foundation for the study of burnout, but that the control dimensions need to be evaluated independently since they appear to be differentially related to the burnout dimensions.     

Job demands,job control,and mental health in an 11-year follow-up study: Normal and reversed relationships

Abstract

Despite numerous studies of the demand-control model, there is a need for more longitudinal studies to test not only the normal, but also the reversed and reciprocal relationships between work characteristics and mental health. There is also a need for more studies of the multiplicative interaction between demands and control with respect to mental health, which is different from the simple additive effect of the two variables. This is a longitudinal study with an exceptionally long period of follow-up (11 years), with the focus on normal as well as reciprocal and reversed causality between work characteristics and mental health, as measured by reliable instruments close to the original definitions of Karasek. The study was based on a sample of 439 Norwegian employees of different occupations who had stayed in the same profession during the follow-up period. The results were in agreement with the hypothesis that low job control, and in particular low control in combination with high demands (“high strain jobs”), has a negative effect on mental health. There was a significant multiplicative interaction between demands and control, indicating a “buffering” effect of job control. Job demands alone were not significantly associated with mental health. The reversed relationship hypothesis was supported for job demands, but not for job control.     

Specific relationships between psychosocial job conditions and job-related stress: A three-level analytic approach

This cross-sectional questionnaire study presents a multi-level analysis on 2565 workers in 188 departments in 36 organizations in the Netherlands. A three-level model is used in which individual workers are nested within departments, which in turn are nested within organizations. Research questions concern (1) the amount and distribution of variance in job-related stress explained for the three levels in the study (individuals, departments, organizations), and (2) the specificity of relationships between psychosocial job demands and job-related stress in the three-level model. Well-being showed slightly more raw variance to be explained at supra-individual levels than strain. The full regression model explained about 35% of the total variance in both work-related strain and well-being. Psychosocial job conditions did not exceed the expected amount of 10 to 15% contribution to this explained variance. These results do not differ from comparable studies that do not use multi-level analysis. The variance distribution in the full model, however, showed unexplained variance to be located at the individual level for both strain and well-being, and at the departmental level only for well-being. This last finding shows a direction for possible improvement of work stress models. Specificity of relationships was also shown: psychological job demands were more strongly related to strain, whereas job content variables (i.e. job variety, job control) were more strongly related to well-being. Results also suggested that social support was more strongly associated with well-being than with strain. Well-being appeared to have a more widely varying range of predictors than strain.     

ENOP: Organizational issues in hospitals

Abstract

The major aim of this study was to examine how job stress in the offshore working environment may affect workers experience of strain. This study also analyses both the main and moderator effect of social support on the association between job stress and strain. The association between strain and absenteeism is also analysed. The analyses are based on a self-completion questionnaire survey among employees on offshore oil installations in the Norwegian part of the North Sea (n = 1137). The data collection was carried out in 1994. A similar study was conducted in 1990. Job stress was found to be associated with job dissatisfaction, as well as experience of strain. Social support from a supervisor had a main effect on strain. Some evidence of the moderating effects of social support were found. The employees who had been absent from work experienced most strain. It is concluded that job stress predicted job dissatisfaction and strain. In turn, strain and absenteeism were associated with each other. These results suggest that improving organizational and social factors should be the focal area in health promotion in the offshore oil industry.     

Employee reactions to behavioural control under conditions of stress: The moderating role of self-efficacy

Extensive research conducted in the occupational stress literature has failed to provide convincing support for the stress-buffering effects of work control on employee adjustment. Drawing on research conducted in the laboratory context, it was proposed that the stress-buffering effects of work control on employee adjustment would be more marked at high, rather than low, levels of self-efficacy. In a sample of 100 customer service representatives, a significant three-way interaction among role conflict, work control and self-efficacy (measured at Time 1) was observed on (low) depersonalization (measured at Time 2). Consistent with expectations, work control reduced the negative effects of work stress on this outcome measure only for employees who perceived high levels of self-efficacy at work. In addition, there was evidence to suggest that self-efficacy moderated the main effects of work control on job satisfaction and somatic health. These findings are discussed in terms of their theoretical contribution to the job strain model, and also in relation to workplace interventions designed to improve levels of employee adjustment.     

Psychosocial safety climate as an antecedent of work characteristics and psychological strain: A multilevel model

Abstract

Psychosocial safety climate (PSC) refers to a specific organizational climate for the psychological health of workers. It is largely determined by management and at low levels is proposed as a latent pathogen for psychosocial risk factors and psychological strain. Using an extended Job Demands-Control-Support framework, we predicted the (24 month) cross-level effects of PSC on psychological strain via work conditions. We used a novel design whereby data from two unrelated samples of nurses working in remote areas were used across time (N=202, Time 1; N=163, Time 2), matched at the work unit level (N= 48). Using hierarchical linear modelling we found that unit PSC assessed by nurses predicted work conditions (workload, control, supervisor support) and psychological strain in different nurses in the same work unit 24 months later. There was evidence that the between-group relationship between unit PSC and psychological strain was mediated via Time 2 work conditions (workload, job control) as well as Time 1 emotional demands. The results support a multilevel work stress model with PSC as a plausible primary cause, or “cause of the causes”, of work-related strain. The study adds to the literature that identifies organizational contextual factors as origins of the work stress process.     

Testing Karasek's learning and strain hypotheses on young workers in their first job

This study tests the core hypotheses of Karasek's job demand-control model: high job demands (workload) in combination with low job control (autonomy) increase strains (job dissatisfaction; strain hypothesis), whereas high job demands in combination with high job control increase learning and development in the job (here: learning new skills in the first job; learning hypothesis). These hypotheses are tested in two ways: (a) the mere combination of both job characteristics is associated with the expected outcomes, and (b) a statistical interaction between both job characteristics in predicting the outcomes is expected. A large dataset (n=2,212) of young workers in their first job was used to test all hypotheses. As young workers are presumably still in the process of adjusting themselves to their work environment, we expected that the effects of work characteristics on work outcomes would be stronger for this group than for more experienced workers. The results confirm both the strain and the learning hypothesis. We found a combined effect of both job characteristics, as well as a statistical interaction between both variables. The lowest level of job satisfaction was found in the “high strain” job, whereas the highest increase in skills was found in the “active” job. The consequences of these findings for theory and practice are discussed.