on a day-to-day basis, within-person fluctuations in mood and work hours were more
important than the stable features of the work environment (Jones et al., 2007).
The model has been influential and it has inspired a number of successful
interventions to increase control and reduce demand e.g. see Bambra et al. (2007),
discussed later in this chapter. However, job redesign attempts have not always been
successful (van der Klink et al., 2001). Critics have suggested that the key variables are
too broad and/or confounded with other work characteristics, leaving the precise
nature of required interventions unclear (e.g. Jones et al., 1998; O’Connor et al.,
2000b). The model has also been criticized for not including individual differences
(e.g. coping characteristics), which have been found to buffer the relationship between
work features and employee well-being (Parkes, 1991; de Rijk et al., 1998). In these
respects the next two models have some advantages.
The job demand–resources model
The job demand–resources model (JD-R) is one of the most recent approaches to work
stress (Demerouti et al., 2001). It addresses some of the criticisms of the above model.
It was originally proposed as a model of burnout. This is a syndrome consisting of
exhaustion, depersonalization and lack of personal accomplishment (Maslach, 1982).
Those working in human service occupations (social workers, teachers, etc.) were
assumed to be particularly vulnerable to burnout but more recently the concept has
been extended to other occupations as the core dimensions of exhaustion and
disengagement may be found in many occupations (Bakker and Demerouti, 2007).
The model has since been used to predict other outcomes, such as depression (Hakanen
et al., 2008) and job satisfaction (Nielsen et al., 2011).
Like the JDC and the ERI, the JD-R model suggests that stress results from a lack
of equilibrium between sets of broadly positive and broadly negative variables. This
model focuses on the equilibrium between job demandsand resources. Job demandsare
defined as the ‘physical, social, or organizational aspects of the job that require
sustained physical and/or psychological (cognitive and emotional) effort or skills and
are therefore associated with certain physiological and/or psychological costs’ (Bakker
and Demerouti, 2007: 312). Job resources, on the other hand consist of a broad range
of aspects of the job that serve to either help the individual to achieve their work goals,
help reduce their job demands or facilitate personal growth and development (Bakker
and Demerouti, 2007). This may include control and rewards as well as social
resources. The model has also been expanded to include personal resources such as
optimism and self-efficacy (Xanthopoulou et al., 2007). It is consistent with the tenets
of the conservation of resources theory (see Chapter 3).
The model suggests two processes, the health impairment process whereby excessive
demands may lead to exhaustion and health problems and the motivational process
whereby job resources may lead to increased work engagement and performance
(Bakker and Demerouti, 2007). A number of studies have now supported these two
core processes in relation to psychological burnout and job engagement (e.g. Schaufeli,
Leiter and Maslach, 2009, Xanthopoulou et al., 2007).
In addition to these main effects, the JD-R model, like the JDC model, proposes
that interactions between the core variables are also important in predicting strain and
motivation. Because of the large number of potential resources and demands, a range
76 STRESS AND HEALTH