The utility of self-rated health in population surveys: the role of bodyweight.

Background: Self-rated health (SRH) is one of the most commonly used summary measures of overall health and well-being available to population scientists due to its ease of administration in large-scale surveys and to its efficacy in predicting mortality. This paper assesses the extent to which SRH is affected by its placement before or after questions about bodyweight on a survey, and whether differences in placement on the questionnaire affects SRH's predictive validity.

Methods: I assessed the validity of SRH in predicting the risk of mortality by comparing outcomes of sample members who were asked to rate their health before reporting on their bodyweight (the control group) and sample members who were asked to rate their health after reporting on their bodyweight (the treatment group). Both the control and treatment group were randomly assigned via an experiment administered as a module in a nationally representative sample of adults in the USA in 2019 (N = 2523).

Results: The odds of reporting a more favorable appraisal of health are 30% lower for sample members who were in the treatment group when compared with the control group. Additionally, the SRH of treatment group members is significantly associated with their risk of mortality, while the SRH of control group members is not.

Conclusion: The findings from this study suggest that for researchers to maximize the utility of SRH, closer attention needs to be paid to the context of the survey within which it asked. SRH is highly sensitive to the questions that precede it, and this sensitivity may in turn mischaracterize the true health of the population that the survey is intending to measure.