Using Anchoring Vignettes in the Evaluation of Breast Cancer Survivors' Quality of Life.

BACKGROUND: Breast cancer survivors often rate their general health as good even though they experience detriments in functioning and multiple symptoms. The hypothesis of this study is that breast cancer survivors changed their frames of reference for evaluating their own health.

METHODS: A sample of 308 breast cancer survivors were asked to assess their state of health on a 0-100 scale. In addition, 2 vignettes (fictional persons suffering from various health complaints) were designed. The cancer survivors were asked to assess the health of the characters in these vignettes as well. A sample of the general population (n = 639) served as controls.

RESULTS: There were only marginal differences between the cancer survivors (M = 65.8) and the controls (M = 65.5) in how they assessed their own state of health. However, the cancer survivors rated the vignette character with physical problems as being significantly healthier compared to the general population (effect size: d = 0.55). The group differences in the assessment of the vignette character with mental problems was markedly lower (d = 0.12).

CONCLUSIONS: It is not sufficient to assess the general self-assessed health state of cancer survivors. Anchoring vignettes are a promising tool for use in correcting for response shift effects.