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1 Work and Employment in the Era of Economic Globalization

The industrial revolution originating in some European countries in the late eighteenth and early nineteenth century, in combination with radical political and societal changes initiated by the French revolution and the independence of the United States of America, are considered decisive turning points in modern human history (Hobsbawm 1968). Economic growth, technological progress, and a substantial transformation of the workforce were achieved, fuelled by core forces of the market economy. Later on, the development of welfare state policies within emerging democracies, including legislation protecting workers’ safety and health, and a broadened access to education and skill development conducive to technological advances contributed to unprecedented productivity, rise in living standards, life expectancy, and societal progress. Yet, trans-national wars and economic crises acted as destructive forces in the development of ‘industrialized’ societies over the past 100 years. Moreover, during this period significant changes in the nature of work and employment occurred. Mass production was transformed by the advent of automation and, more recently, by pioneering developments of information and communication technology. Service occupations and professions, and administrative jobs continued to expand, shifting the workforce of high income countries from a manufacturing-based industrial towards an information-based economy (Piore and Sabel 1984). Alongside these developments the composition of the labour force became more diverse, with an increase of older workers, working women, and immigrant workers. Employment relations also changed significantly as flexible job arrangements largely replaced previously dominating standard contracts with more stability and long-term career prospects.

It is generally agreed that a process termed ‘economic (or neo-liberal) globalization’ became visible during the 1970s and 1980s in leading economies of high income countries, impacting progressively the world’s remaining economies. Distinct from previous trans-national developments of economic, social and cultural exchange and interdependence contemporary globalization is characterized by the fact that free market principles in conjunction with ground-breaking innovations in information and communication technology spread over the world, stimulating large flows of transnational capital, trade, and workforce. This flow of capital, trade, and labor force was, and continues to be, promoted by the creation of international institutions, such as the International Monetary Fund, the World Trade Organization, and the World Bank, as well as by intergovernmental trade liberalization resulting from the deregulation of national financial markets. The deregulation was initiated in an era of economic recession, guided by neo-liberal principles recommending an end to fixed currency exchange rates, a private sector growth at the expense of the public sector, and a weakening of national legislation, welfare state and social policies in conjunction with reduced governmental spending (Labonte 2015).

The expansion of financial markets operating worldwide with risky capital exchanges, and the growing power of transnational corporations originating essentially from the three regions of United States of America, North-Western Europe, and Japan most pervasively characterize the current state of economic globalization. Proponents of this development claim that the creation of new jobs in developing countries and the concomitant global economic growth decrease poverty, improve living conditions including health, and result in strengthening international human rights in less developed parts of the world (Sachs 2005). At the same time, the ‘flexible accumulation’ of capitalist production alongside a ‘spacial restructuring’ of work on a global scale promotes large income inequalities between and within countries and results in significant changes of employment relations and working conditions in economically developed parts of the world (Kalleberg 2009). Importantly, a transnational labor market results from the ‘spacialization’ of production and workforce, aggravated by the entry of millions of working people from China, India, and the former Soviet bloc countries into the global labor pool. With a resulting growth in economic competition and increased pressures for cost-containment, large parts of the workforce in high income countries are experiencing an increase of their workload and work intensity. High work pressure often goes along with higher job instability and insecurity, with adverse long-term effects on health and wellbeing (Gallie 2013) (see below).

Several determinants of heightened uncertainty of one’s job in the context of economic globalization were identified. First, with growing pressure on return on investment employers aimed at reducing labor costs, specifically by implementing distinct restructuring strategies. These strategies are known as off-shoring, downsizing, and outsourcing. As a result, layoffs, forced occupational mobility and involuntary part-time employment became more frequent (Cooper et al. 2012). Second, supported by technological advances and economic constraints, job arrangements and employment contracts became more flexible. A rise in non-standard work arrangements has been observed, such as temporary agency-based work, part-time work, fixed term contingent work, and independent contracting. As a consequence, “the standard employment relationship, in which workers were assumed to work full-time for a particular employer at the employer’s place of work…was eroding… which led to a growth in precarious work and transformations in the nature of the employment relationship” (Kalleberg 2009, p. 3). Although the notion of precarious work includes disadvantaged conditions such as lack of control of one’s job environment and task, lack of alternative job opportunities and poor pay, job insecurity is probably its most eminent, most frequent feature. Insecure jobs are now increasingly spreading from the secondary labor market to considerable parts of the primary labor market, where they affect higher qualified employees and some professional groups as well. As a consequence, a growth in perceived job insecurity and of nonstandard flexible work arrangements has been observed among several workforces in advanced societies (Gallie 2013; Quinlan et al. 2001). Third, neo-liberal market forces resulted in a weakening of legal regulations incorporated in national social and labor policies, thus reducing workers’ opportunities of experiencing employment stability and fair retirement benefits. The chances of preventing this risk-enhancing process were critically reduced by a global decline in union membership and a reduced power of workers’ collective voice of defending their rights (Moutsatos 2009).

In conclusion, significant changes in the nature of work and employment occurred during the past several decades that can briefly be summarized at three levels. First, with the advent of new technologies and new societal demands employment sectors in high income countries shifted from industrial mass and lean production towards service delivery and information/communication technology-driven jobs. Although physically strenuous work and exposure to main occupational hazards of industrial production continue to pose serious challenges to workers’ health and safety, the threats of a health-adverse psychosocial work environment are becoming more widespread and more visible with this shift, and they contribute to a growing burden of work-related diseases. Second, as a consequence of different drivers, mainstream employment relations and job trajectories with long-standing continuity and security were increasingly replaced by more flexible arrangements, including mobility, retraining, de-standardization of employment contracts, and growth of job insecurity. In part, these developments were supported by demographic changes in the composition of workforces, in particular by an aging population, an increasing participation of women in the labor market, and a diversification of working people in terms of cultural background and training. Third, with the advent of economic globalization, growing competition between transnational companies and the constraints of financial markets resulted in a sizeable increase of work pressure in many employment sectors in high income countries. At the same time, job stability and promotion prospects decreased – and continue to decrease – not only in the periphery of labor markets, but increasingly in its well-trained central segments.

2 The Role of Psychosocial Stress at Work

As was mentioned, the spectrum of occupational exposures with potential impact on health has changed rather markedly during this transformation. While traditional hazards still prevail in certain sectors of the labour market, the majority of employed people are now confronted with a variety of mental and emotional demands, threats or conflicts rather than with toxic substances and environments. There has been a general recognition that the importance of work for health goes beyond traditional occupational diseases. Moreover, the established approach of occupational medicine with its focus on occupational toxicology, noise, temperature and similar conditions needs to be extended to include a wide spectrum of work-related stressors that affect working people’s perceptions, cognitions, emotions, and motivations. To this end, theoretical and methodological knowledge from social and behavioural sciences, specifically from psychology and sociology is required that complements the knowledge obtained from basic sciences, such as physics, chemistry, and biology. The stress paradigm offers a most promising approach to deal with this major challenge of modern, current occupational health research.

The notion of ‘stress’ as a scientifically useful term differs from its widespread popular use in everyday language in important ways. Stress defines a reaction to a challenge (stressor) from the external world or from within the organism that interrupts or threatens the usual behaviour and normal functioning of a person and that requires specific efforts to meet the challenge. These efforts are termed ‘coping’ and include personal competencies and capabilities as well as interpersonal, socio-environmental support. Stressors can occur in the natural and built environment as well as in the social environments where people live and work, either as acute, unexpected events (e.g. earthquake, fire, terrorist attack) or as chronic, recurrent threats (e.g. drought, starvation, long-term unemployment). In terms of frequency, duration, and impact on health major chronic stressors originating from the social environment deserve primary attention (Weiner 1992). Adverse psychosocial work environments are one such type of chronic social stressors.

A second difference between everyday and scientific notions of stress concerns the distinction of several dimensions of a person’s response to a stressor. In scientific terms, the following dimensions are distinguished: the cognitive, the affective or emotional, the physiological, and the behavioural response. At the cognitive level, a challenge is appraised according to its degree of threat or harm. This appraisal is paralleled – or sometimes preceded – by negative or positive affective responses, where the experience of threat goes along with intense negative emotions of anger, irritation, or anxiety. At the physiological level, stress reactions activate the autonomic nervous system and the organism’s innate stress axes. The primary biological systems activated during stress are the hypothalamic-pituitary- adrenal (HPA) and sympatho-adrenomedullary axes (Steptoe and Kivimäki 2012). The long-term consequences of sustained activation of stress axes, mediated by endocrine, immune, and autonomic nervous system responses, trigger a state of ‘allostatic load’ within distinct organ systems, resulting in the development of manifest diseases (McEwen 2007; see Chaps. 5, 6, and 7). At the behavioural level, stress responses in terms of evolutionary old patterns of fight or flight are often prevented in modern societies by mechanisms of social control, thereby intensifying the physiological reactions (Elias 1997).

How can we define those critical aspects of adverse psychosocial work environments that act as chronic social stressors, thereby affecting the working persons’ health and wellbeing? Given the complexities and variations of multiple modern work environments and employment conditions there is a need to reduce this complexity by selectively focusing on distinct components that are assumed to produce tangible effects on workers’ health. To this end, a theoretical model is needed. A theoretical model offers at least three advantages. First, it proposes an analytical focus by identifying a general principle that is expected to explain the associations between stressful aspects of work and the working people’s health. Proposing a theoretical model is a creative intellectual activity and, at the same time, a risky endeavour, as an empirical test of its predictions may fail. Once a theoretical model has been measured by a standardised assessment approach, cumulative empirical evidence on its explanatory contributions can be achieved, through recurrent testing in epidemiological and experimental studies. As a third advantage of a theoretical model resulting from this second gain, successful explanations or predictions derived from the model can be used to guide actions that aim at improving work and employment settings and reducing the burden of work-related disorders.

As mentioned, every theoretical model is inherently limited due its selective analytical focus. Therefore, there may always be a trade-off in applying a model between the limitations resulting from its selective analytical focus and the desire to understand the richness and complexity of the real world. Several decades of research along these lines resulted in the proposition and test of a variety of theoretical models of a psychosocial work environment with relevance to health (for review e.g. Cartwright and Cooper 2009). Some of these models received prominence in terms of their diffusion across the research community and in terms of their contribution towards explaining working people’s health and wellbeing. Among them, in a historical perspective, the following approaches are noteworthy: ‘person-environment fit’ (French et al. 1982; Edwards et al. 1998), ‘demand-.control’ (Karasek 1979; Karasek and Theorell 1990), ‘effort-reward imbalance’ (Siegrist 1996), ‘organizational injustice’ (Greenberg and Cohen 1982; Elovainio et al. 2002), and ‘job demands-resources’ (Demerouti et al. 2001).

While a more detailed description of these models is given below, it is probably accurate to observe that each concept was developed in a specific socio-cultural and socio-economic context. For instance, ‘person-environment’ addresses the role of individual perceptions and coping efforts in adapting to job environments, with a major interest in achieving optimal correspondence between persons’ abilities and environmental demands and supplies. This important extension of previous uni-dimensional approaches nevertheless puts more weight on individual adaptation to given work environments than on changing environments (Karasek and Theorell 1990, p. 95). This is well understandable given the major scientific input from important psychological advances in personality and organizational behaviour research during that time. As a result, improving recruitment, selection, and training of persons entering the labour market seems to be a primary practical application of this model’s insights (Edwards et al. 1998, p. 58). It may be of interest to note that this concept originated in the context of a booming industrial labour market and sustained economic growth in the United States in the 1960s and 1970s, directing attention to workers’ job satisfaction, such as qualification, career advancement, or working climate rather than to issues of job insecurity or job loss, forced occupational mobility, or poor salary. To some extent, the same holds true for the concept of organizational injustice which places its main emphasis on fair procedures of treating employees, of appropriated leadership behaviour, and of improved flows of information and communication within organizations. Embedded in emerging scientific developments of organizational and occupational psychology and management sciences in the 1970s in the United States and Europe, it disregarded broader labour market developments.

Different from these traditions, the demand-control model is rooted in a sociological approach focusing on characteristics of job task structures and features. It gives rise to organizational change in terms of job redesign, and it aims at strengthening workers’ control over their job tasks, stimulating job enrichment and skill development. The model has been – and continues to be – important for improving trade unions’ efforts towards a democratization of work organization and the management of enterprises, and it has even far-reaching implications of challenging the utilitarian approach towards material production and economic growth (Karasek and Theorell 1990). Despite these merits of representing a broad spectrum of scientific scholarship, including the discussion of personality factors in the work process, the model, in its measurement approach, must be considered a ‘black box’ concept analysing distinct combinations of features of job tasks and, with respect to the addition of the dimension of social support at work, of its immediate social environment. Importantly, the authors confirm their unique focus on job tasks in their basic critique of Taylor’s influential principles of work organization, claiming that “the three major oversights in Taylor’s prescription for job design related to psychological demands, control, and social support” (Karasek and Theorell 1990, p. 24). As such, the demand-control-support model still heavily relies on a stage of economic development where industrial production with inherent forms of division of labour plays a core role, and where employees are performing their work in the frame of hierarchically structured organizations.

‘Effort-reward imbalance’ has been proposed as a complementary model of psychosocial stress at work that addresses more recent economic developments by focussing on the employment contract as the core element of employment relations, rather than on job task features. With the consequences of economic globalization described above, the nature and quality of employment contracts gained renewed prominence, given a growth of insecure and precarious work, short-term contracts, and new forms of flexible employment arrangements. Moreover, with associated developments of information and communication technologies and automation, temporal and spatial constraints of performing work within traditional organizational frames of enterprises were diminished, while the employment contract continues to be of key importance in new forms of work arrangements, such as home-based or other forms of distant work, independent contracting, and in a variety of service job conditions. The next section describes this model in more detail.

3 The Model of Effort-Reward Imbalance at Work

This theoretical concept is concerned with stressful features of the employment or work contract. It was developed by this author and his group with a selective focus on the notion of social reciprocity in costly transactions (Siegrist 1996). Social reciprocity has been identified as a fundamental, evolutionary stable principle of collaborative human exchange (Gouldner 1960). According to this principle, any costly transaction provided by person A to person B that has some utility to B is expected to be returned by person B to A. Exchange expectancy does not implicate full identity of the service in return, but it is essential that this activity meets some agreed-upon standard of equivalence. Failed reciprocity results from situations where service in return is either denied or does not meet the agreed-upon level of equivalence. To secure equivalence of return in crucial types of costly transactions, social contracts have been established as a universal societal institution. The work contract (or contract of employment) is one such type where efforts are expected to be delivered by employees in exchange for rewards provided by the employer. Three basic types of rewards are transmitted in this case: salary or wage (financial reward), career promotion or job security (status-related reward), and esteem or recognition (socio-emotional reward). Importantly, contracts of employment do not specify efforts and rewards in all details, but provide some room of flexibility and adaptation.

The model of effort-reward imbalance at work asserts that lack of reciprocity in terms of high cost spent and low gain received in turn occurs frequently under specific conditions. ‘Dependency’ is one such condition, defined by situations where workers have no alternative choice in the labour market. For instance, unskilled or semi-skilled workers, elderly employees, or those with restricted mobility or reduced work ability may be susceptible to unfair contractual transaction as the incentives of paying non-equitable rewards are high for employers, while the risks of rejecting this transaction by employees are low, due to the fact that they have no alternative choice. ‘Dependency’ is relatively frequent in modern economies with a globalized labour market (see above). While this labour market offers jobs with good quality to better qualified parts of the workforce it confronts less skilled or otherwise disadvantaged parts with job instability or job loss due to mergers, organisational downsizing, rapid technological change, and growing economic competition. In times of economic globalization, forced competition equally occurs among better qualified parts of the work force, and among them, a second condition of failed reciprocity at work, termed ‘strategic choice’, may matter. Here, people accept the experience of ‘high cost/low gain’ in their employment for a certain time, often without being forced to do so, because they tend to improve their chances of career promotion and related rewards at a later stage. This pattern is frequently observed in early stages of professional careers and in jobs characterized by heavy competition. As anticipatory investments are made on the basis of insecure return expectancy, the risk of failed success after long-lasting efforts is considerable.

The notion of effort at work implies both an extrinsic demand to which the working person responds as well as a subjective motivation to match the demand. In most instances, matching the demands is part of the control structures established in organizations, thus leaving little room for variations of subjective motivation. Yet, demands are likely to be exceeded in situations of strong informal pressure exerted by a competing work team (e.g. group piece work). Similarly, demands are likely to be exceeded if people are characterized by a motivational pattern of excessive work-related ‘over-commitment’. Consciously or unconsciously, they may strive towards continuously high achievement because of their underlying need for approval and esteem at work. This motivation contributes to ‘high cost/low gain’ experience at work even in the absence of extrinsic pressure.

To summarize, the model of effort-reward imbalance at work maintains that failed contractual reciprocity in terms of high cost and low gain is often experienced by people who have no alternative choice in the labour market, by those exposed to heavy job competition, and by those who are overcommitted to their work. As these conditions are expected to occur across different sectors of employment, in a variety of jobs and in different socio-economic and socio-cultural contexts the model’s claim may be relevant for working populations in several parts of the world, but specifically in labour markets in times of a globalized economy.

In a sociological perspective, the model stresses the core social role of paid work in adult life, and it considers the powerful effects of socio-structural inequalities on status acquisition and status control as elaborated by the classical work of Robert K. Merton (1968). According to Merton, socio-structural conditions act as external constraints against individual choices where the chances of realizing a desired goal depend on the person’s location in the vertical social structure. The vertical social structure distinguishes status positions according to access to core resources, such as authority, power, influence and prestige. Therefore, the social opportunity structure in general, and the opportunity structure of the labour market more specifically, affect people’s unequal life chances, including the quality of work and related rewards. Being confined to jobs defined by high cost and low gain, being locked in unrewarding work environments, and experiencing recurrent relative deprivation negatively affect the health and wellbeing of working people.

3.1 The Model’s Hypotheses and Its Stress-Theoretical Basis

A graphical illustration of the model is depicted in Fig. 1.1 (see also Chap. 2). These are the model’s core research hypotheses linking stressful psychosocial work with adverse health outcomes:

  1. 1.

    Each component of the model, defined by the scales ‘effort’, ‘reward’, and ‘over-commitment’, exerts separate effects on the health outcome under study. In general, these effects reflect a dose-response relationship.

  2. 2.

    The size of effect on health produced by a combined measure quantifying the imbalance between high effort and low reward exceeds the size of effect on health produced by each single component (e.g. as demonstrated by the individually assessed ‘effort/reward ratio’).

  3. 3.

    The personal coping pattern ‘over-commitment’ moderates the effect size of effort-reward imbalance on health (interaction term). Among people scoring high on over-commitment this effect is significantly stronger than among people scoring low on this pattern of coping.

Fig. 1.1
figure 1

The model of effort-reward imbalance at work

Full size image

As there are two types of imbalance between effort and reward, high effort with low reward and low effort with high reward, it is crucial to distinguish their different significance in stress-theoretical terms. As explained in more detail below, primacy with regard to impact on health is accorded to the former type of imbalance. Accordingly, an additional hypothesis states that the relative risk of stress-related disorder associated with high effort in combination with low reward at work is always higher than the risk associated with low effort in combination with high reward. A further refined hypothesis of this model maintains that each one of the three reward components depicted in Fig. 1.1 exerts effects of similar strength on health, thus supporting the notion of comparable importance of material and non-material occupational rewards for health and wellbeing.

Turning to the stress-theoretical basis of the model it is obvious that experiencing effort-reward imbalance at work is particularly distressing as it frustrates basic expectations of equivalence of return in costly transactions. Most importantly, the recurrent experience of failed reciprocity is expected to afflict the health and wellbeing of working people by compromising their self-esteem and by eliciting negative emotions and related psychobiological stress responses. As mentioned, continued sustained stress responses exert adverse long-term consequences for stress-related mental and physical disorders (McEwen 2007; see also Henry and Stephens 1977; Weiner 1992).

The experience of effort-reward imbalance at work due to unfair exchange, trust violation, or broken promise is assumed to activate distinct areas in the brain reward circuits, including nucleus accumbens, anterior cingulated cortex, and insula (Schultz 2006). This activation suppresses the production of dopamine and oxytocin, i.e. neurotransmitters associated with pleasurable emotions and stress-buffering properties. Moreover, activation of the insula is associated with the experience of physical and emotional pain, and with strong visceral and somatic sensations (Baumgartner et al. 2009; Singer et al. 2004). If combined with the occurrence of threats to a person’s self or social status, these processes of sustained activation may interfere with inbuilt regulatory systems of the body, driven by extensively aroused stress axes and impaired compensating bodily anti-stress mechanisms, thus triggering the development of stress-related disorders. Importantly, recent neuroscience research demonstrates that insular activation is modulated by the magnitude of loss following effort, and that the intensity of positive stimulation of the brain reward circuits depends on the amount of effort previously expended (Hernandez Lallement et al. 2014). It seems that the brain’s reward circuitry is sensitive to the experience of disadvantageous inequality in social exchange (Tricomi et al. 2010). While this recent evidence from neuroscience research is in accordance with basic assumptions of the effort-reward imbalance model, further studies are needed to unravel the links between sustained experience of reward deficiency at work and the development of stress-related disorders, triggered by the described psychobiological processes (see also Chap. 7).

3.2 Distinct Approaches Towards Dealing with Inequity

This model has not been conceptualized at a single early stage of my scientific work. Rather, it gradually evolved over time, starting with early collaborative research that explored the psychosocial history preceding the incidence of young men’s first myocardial infarction (Siegrist 1984; Siegrist et al. 1986). Before the final conceptualisation and measurement of the model were accomplished, its main hypotheses were tested in the frame of a prospective study of a cohort of blue-collar industrial workers and their risks of experiencing coronary heart disease (Siegrist et al. 1990; see below Chap. 5). In the course of advancing the model, similarities with, and differences from related theoretical notions became evident. Whereas these similarities and differences with the demand-control model are discussed below, those related to different conceptualisations of the core notion of inequity are addressed here. Two such conceptualisations are particularly relevant in this context, Adam’s (1965) inequity theory, and the model of organizational injustice (Greenberg 2010).

The principle of social reciprocity, elaborated in a sociological perspective by Gouldner (1960), is central to the effort-reward imbalance model. The overarching significance of this principle is due to the fact that it protects people from stressful, devastating experiences of deprivation, deception or even fraud evolving from its violation. Accordingly, justice of exchange in interpersonal transactions is realised to the extent that taking unjustified advantage of other people’s investments in exchange can be prevented. In a certain contrast to this argument, an influential social psychological theory of inequity proposed by Adams (1965) distinguishes between two deviations from the principle of reciprocity of exchange, ‘over-fitting’ and ‘under-fitting’. In the first case, the gains received outmatch the invested costs, whereas in the latter case, costs exceed the experienced gains. Equity theory posits that both states trigger some kind of inequity aversion that motivates people to reduce these discrepancies by behavioural or cognitive changes. Yet, a stronger motivation of change is expected in case of under-fitting than in case of over-fitting, given the powerful impact of loss experience. As Adams’ main interest was to understand adaptive behavioural changes following perceived inequity rather than to explore potential effects on emotion and wellbeing, this latter assumption was not tested in the frame of inequity theory. However, the important role of avoiding ‘under-fitting’ and related loss aversion in guiding economic decision- making and in securing people’s emotional wellbeing was demonstrated in the path-breaking experiments of Kahneman and Tversky (1979), and was supported by a broad range of subsequent research including the influential theory of conservation of resources (Hobfoll 1989).

A second notion of Adam’s social-psychological inequity theory deserves attention as it has direct relevance to the effort-reward imbalance model, the notion of two types of reference standards (Adams 1965). The first standard, termed ‘intrinsic’, is weighing the costs of effort against the gains of reward, whereas the second standard, termed ‘extrinsic’, is weighing one’s own gains relative to one’s costs with the gains obtained by significant others for similar costs. According to inequity theory, both reference standards are of similar importance in evaluating the equity or fairness of exchange. In contrast, the effort-reward imbalance model accords primacy to the intrinsic reference standard, given a prominent role of the ‘evolutionary old’ principle of social reciprocity (see above). A decisive role of intrinsic reference standards has been demonstrated, for instance, with regard to the evaluation of fair earnings (e.g. Fehr and Fischbacher 2003). To quote just one example: In a large survey, judging one’s own earning as unfair (intrinsic reference standard) was strongly associated with poor health even after adjusting for the confounding factor of horizontal social comparison (extrinsic reference standard) (Falk et al. 2011). In summary, inequity theory has contributed to significant progress in understanding the unfairness of social exchange. Yet, as argued here, when applying this approach to the analysis of stressful work, some further specifications are needed.

The concept of ‘organizational injustice’ that was elaborated in the context of organizational psychology and management sciences in the 1970s and 1980s (Greenberg 2010) is largely based on Adam’s inequity theory. It is concerned with the analysis of perceived inequities of people’s behaviours within formal organizations, mostly in the frame of work and employment. Four types of injustice are usually distinguished. ‘Procedural injustice’ is defined as the perceived deviance from established rules of decision-making and from applying agreed-upon standards of judging the performance of employees. ‘Interactional (or relational) injustice’ describes the unequal treatment of persons within organizations in everyday interactions, e.g. with regard to respect and communication. ‘Informational injustice’ is introduced to describe unequal access to, and share of relevant information within the organization. Finally, ‘distributive injustice’ is defined as the perceived inequity of an organization’s distribution of valuable goods, resources, and services to its members. It is this last type, distributive injustice, which may interfere with the core notion of effort-reward imbalance. However, distributive justice within an organisation is primarily concerned with social comparison processes between its members, and in this regard the extrinsic reference standard dominates the evaluations of fair or unfair shares. Thus, a potential conceptual overlap between the notions of distributive justice and justice of exchange can be avoided by pointing to the different weight of extrinsic versus intrinsic reference standards in the respective concepts, as explained.

Finally, when discussing distinct concepts of inequity, the differences in setting priorities for policy implications inherent in the models discussed so far need to be emphasized. Inequity theory (Adams 1965), organizational injustice (Greenberg 2010), as well as the related concept of psychological contract in organizations (Rousseau and McLean Parks 1992), are ultimately directed towards understanding and improving human relations in organizational settings. By improving leadership, communication and flow of information, by developing more appropriate forms of cooperation and by strengthening the organization’s social capital the practical implications of this research are clearly far-reaching. Yet, different from these concepts, ‘effort-reward imbalance’ addresses tangible aspects of the opportunity structure of labour markets (e.g. job security, promotion prospects, adequate earnings), thus pointing to structural aspects of improving work and employment within and beyond the level of organisations (see also Chaps. 15 and 16). Despite this difference, both approaches complement each other and contribute to better health of working people.

4 Comparing Complementary Models of Stressful Work

As every theoretical model of stressful psychosocial work is inherently selective research in this field is confronted with two challenges. First, a convincing argument has to be given that each model offers an explanatory approach that is sufficiently distinct from knowledge that is already available. Second, in empirical research, the independent explanatory power of each model needs to be demonstrated, thus confirming its complementary nature. Concerning the first challenge, the main conceptual differences between ‘effort-reward imbalance’ and ‘organisational injustice’ were already discussed. Can similar arguments be given in case of the other theoretical concepts mentioned earlier?

It is not easy to give a succinct summary of ‘person-environment’ theory as it has undergone several refinements between the early 1960s and the late 1990s (Edwards et al. 1998). Its fundamental premise claims that stress arises from a misfit between the working person and the environment, and that this misfit is best analysed in terms of objective and subjective representations of the person and environment. According to this theory, subjective misfit matters more for the workers’ strain than objective misfit, and this holds true for misfit between extrinsic demands and personal abilities as well as for misfit between supplies and personal needs. Although the theory provides a conceptual framework for understanding the relationships between these two types of misfit and strain it does not specify the content of its core dimensions (Edwards et al. 1998, p. 39). Moreover, at the methodological level, measures of person and environment were often collapsed rather than separated in empirical studies, thus complicating the development of cumulative knowledge. For these reasons, the opportunities of directly comparing ‘person-environment fit’ with concurrent theoretical approaches are limited.

‘Demand-control’ is one such concurrent theoretical model that must be considered the most widely used approach towards studying health-adverse psychosocial work environments. It was introduced by sociologist Robert Karasek (1979) and further developed by Karasek and Theorell (1990). It posits that stressful experience at work results from a distinct job task profile defined by two dimensions, the psychological demands put on the working person and the degree of control available to the person to perform the required task. Jobs defined by high demands and low control are stressful because they limit the individual’s autonomy and sense of control while generating continued pressure (‘high job strain’). Under these conditions, excessive arousal of the autonomic nervous system is expected to occur that is not compensated by a relaxation response following the experience of control and mastery. Low level of control or decision latitude manifests itself in two ways, as lack of decision authority over one’s tasks, and as low level of skill utilization, as evidenced by monotonous, repetitive work. A different job task profile ‘(active job’), defined by high demands in combination with high level of control, exerts more positive effects on the working person. Active jobs enable individuals to experience positive stimulation, success, and self-efficacy. The recurrent experience of control and mastery at work is associated with positive emotions and active learning, thus protecting the working persons from the risk of developing stress-related disorders. Inherent in these categories of job task profiles is some notion of social hierarchy. Obviously, active jobs are more likely to be assigned to better educated people and those in leadership positions, whereas high strain jobs are more prevalent among skilled, semi- or unskilled workers. It is important to recognize that this is a bi-directional model which, in its negative part, is based on the stress- theoretical notion of limited control of challenging demands. In its positive part, it is based on the notion of active learning and skill development through successful coping with stimulating tasks.

‘Demand-control’ and ‘effort-reward imbalance’ differ in important ways. As mentioned, the former’s analytical focus is on job task characteristics while contractual employment relations define the latter model’s focus. Moreover, ‘demand- control’ has been developed with the intention of overcoming outdated conceptions of work organisation and economic growth within the frame of industrial societies, whereas. ‘effort-reward imbalance’ addresses reward deficiencies of people exposed to labour market constraints in a globalized economy. A second difference relates to the role of person characteristics within the two models. While ‘demand-control’ considers exclusively situational characteristics, ‘effort-reward imbalance’ integrates person characteristics in terms of the coping pattern of over-commitment in its set of hypotheses. Third, the stress-theoretical basis differs to some extent between the models as threat to control and threat to reward may activate partly different brain circuits implicated in the stress response. Finally, at the level of basic philosophical orientations, ‘demand-control’ argues in favour of developing a new model of productivity that meets human needs beyond material consumption, unfolding people’s capabilities and creativity. By emphasizing the importance of justice of exchange, social recognition and appreciation for health and wellbeing, ‘effort-reward imbalance’ opens a window of opportunity in favour of an economy that challenges the dominance of egoistic profit by valuing trust and fairness.

More recently, two versions of a further model termed ‘job demands-resources’ were proposed in the context of extensive research on burnout (Demerouti et al. 2001; Schaufeli and Bakker 2004). The first version builds on the demand-control-support model as it considers control, support and feedback as job resources, while extending the definition of demands beyond those captured by the former model. In this version, the authors posit that job resources mitigate the negative effect of job demands on exhaustion and burnout. In an updated second version, negative (burnout) and positive (work commitment) psychological states are defined as outcomes of different constellations of job demands and job resources, thus offering a ‘pathogenic’ as well as a ‘salutogenic’ perspective (Schaufeli and Taris 2014). Motivational processes act as mediators linking job resources with positive performance outcomes, whereas an imbalance between high demands and low resources triggers burnout and associated health problems. Further specifications of the concept concern the introduction of distinct personal resources and vulnerabilities. In a recent review authors confirm that the ‘job demands-resources’ model “is heuristic in nature and represents a way of thinking about how job (and recently also personal) characteristics may influence employee health, well-being, and motivation” (Schaufeli and Taris 2014, p. 44). The fact that all sorts of demands, resources, and outcomes can be included in the model can be interpreted as a strength, but equally so as a weakness. In the context of this discussion the model’s lack of specificity complicates a direct comparison of similarities with, and differences from ‘effort-reward imbalance’.

Having discussed the first challenge I now turn to the second challenge, i.e. the need of demonstrating the independent explanatory power of each model in comparative empirical studies. Up to now, with the exception of a few publications focusing on ‘organizational injustice’ (Kivimäki et al. 2007; Ndjaboué et al. 2012), respective research has been limited to comparisons of the demand-control and the effort-reward imbalance models. In several of the following chapters, respective evidence is presented and discussed. Overall, it can be concluded that either model maintains its strength in explaining health after respective statistical adjustment. Moreover, several reports document additive effects on health resulting from their combination. It is hoped that more comparative research will be conducted along these lines in the near future.

5 Concluding Remarks

This chapter has delineated the theoretical background of the effort-reward imbalance model of psychosocial stress at work. The model has been explained in the framework of recent worldwide developments of work and employment directed by the process of economic globalization. Economic globalization offers opportunities of growth and development, but at the same time carries substantial risks that may threaten the health and wellbeing of millions of working people around the globe. It is therefore important to monitor related risks and to develop preventive measures that aim at reducing the burden of work stress-related diseases. Using available scientific evidence and measurement tools based on theoretical models such as effort-reward imbalance can be a useful and promising step towards this end. In addition to an extended interpretation of this conceptual approach the chapter discussed similarities with, and differences from complementary theoretical concepts in this field of research, a strategy that is needed given the selective nature of each model in view of the complexity and diversity of modern work environments. More specifically, major features of ‘demand-control’, ‘person-environment fit’, ‘organizational injustice’, and ‘job demands-resources’ were elaborated, with an understanding that this selection is far from complete.