Using Anchoring Vignettes to Improve Comparability of Self-Reported Health Measures: Evidence on Shifting Expectations for Health in Aging Populations

Joshua A. Salomon, World Health Organization (WHO)
Ajay Tandon, World Health Organization (WHO)
Christopher J.L. Murray, World Health Organization (WHO)

Longitudinal studies on health in aging populations require data that are reliable, valid and comparable across individuals and over time. One challenge to comparability arises from variation in interpretation of categorical response scales, e.g. due to changing expectations for health. Strategies for enhancing comparability of self-reported health demand augmentation of existing survey instruments and analytical models. This paper introduces the concept of anchoring vignettes to position self-assessments on a comparable scale. Anchoring vignettes describe hypothetical individuals that respondents rate using the same questions used in self-assessments. Because levels in vignettes are fixed, variation in vignette ratings illuminates differences in response category cutpoints. We present examples of anchoring vignettes from an ongoing multi-country survey study, discuss practical issues on design, application and evaluation of vignettes, and demonstrate the use of vignettes to characterize changing norms for health over the life course and adjust self-reported health measures accordingly.