Objectives: To examine whether any response shift in quality of life (QoL) assessment over the course of a cardiac rehabilitation (CR) programme could be explained by changes in individuals' internal standards (recalibration), values (reprioritization), and/or conceptualization of QoL and the extent to which any response shift could be explained by health locus of control, optimism, and coping strategy.
Design: Longitudinal survey design.
Methods: The schedule for evaluation of individual QoL-direct weighting (SEIQoL-DW) was administered at the beginning and end of a CR programme. At the end of the programme, the SEIQoL-DW then-test was also administered to measure response shift. A total of 57 participants completed these measures and other measures to assess health locus of control, optimism, and coping.
Results: Response shift effects were observed in this population mainly due to recalibration. When response shift was incorporated into the analysis of QoL a larger treatment effect was observed. Active coping as a mechanism in the response shift model was found to have a significant positive correlation with response shift.
Conclusion: This study showed that response shift occurs during CR. The occurrence of response shift in QoL ratings over time for this population could have implications for the estimation of the effectiveness of the intervention.