This article reports the results of a randomized field
experiment that tested the effects of a control-enhancing stress intervention
among unit managers of a trucking company. Individuals who managed geographically
dispersed profit centers were randomly assigned to either an intervention
group (N = 34) or a no-intervention group
(N = 30). The intervention increased perceptions of control
after 4 months, but only for those managers with supportive supervisors. In
conjunction with supervisory support, the intervention produced improvements in
job satisfaction, but not general well-being outcomes. The impact of the
intervention and supervisory support on satisfaction was fully mediated by control
perceptions.