Does Job Control Moderate Work Demands’ Nonlinear Association With Job Strain? A Two-Sample Study Using Human Service Case Managers

ABSTRACT

Four decades of research on the influential demand-control (DC) model has yielded inconsistent and contradictory findings. The present study addressed this issue in two innovative ways. First, the DC model was integrated with conservation of resources theory. Next, this original theoretical synthesis was tested on 826 case managers from two different types of public human service agencies. Findings confirmed both hypothesized nonlinear demand by linear control interactions. Data not only make a new contribution to the human service literature, but also clarify forty years of conflicting DC research. Implications for human service workforce management and DC model theory are discussed.

KEYWORDS:

• Conservation of resources theory
• demand-control model
• human services
• job strain
• social work

Acknowledgment

The author would like to acknowledge Beula and Vincent Mack’s invaluable assistance toward the completion of this manuscript.

Notes

¹ Although no empirical evidence exist for this prediction, this study assumes that work-related strategies are best used when work demands are lower to intermediate levels, whereas at-work respite activities are best employed when work demands are at their highest levels. If work demands are manageable, engaging in at-work respites create a backlog of completable, but unfinished tasks or activities, which should elevate job strain. Conversely, work-related strategies deplete resources; and, as such, are less effective than at-work respite activities at preserving energetic resources when work demands are experienced as challenging.

² Warr’s (2013) vitamin model makes a similar prediction.

³ This argument is consistent with Miller’s (1979) minimax hypothesis which states that “a person who has control over an aversive event insures having a lower maximum danger than a person without control” (p. 294).

⁴ Mean subgroup scores across the upward diagonal of the three-dimensional demand-control matrix are 16.3, 11.0 (mean of two scores), and 33.9 (Karasek, 1979, p. 294).

⁵ Mean subgroup scores across the upward diagonal of the three-dimensional demand-control matrix are 7.1, 4.9 (mean of four scores), and 29.3 (Karasek, 1979, p. 298).

⁶ This idea is in alignment with de Jonge and Dormann’s (2006) triple matching principle. Greater scheduling control, for example, should reduce high time pressure demands’ negative effect on work fatigue.