Imprecise health beliefs and health behavior

This paper examines belief imprecision in the context of COVID-19, when uncertainty about health outcomes was widespread. We survey a sample of young adults a few months after the onset of the pandemic. We elicit individuals' minimum and maximum subjective probabilities of different health outcomes, and define belief imprecision as the range between these values. We document substantial heterogeneity in the degree of imprecision across respondents, which remains largely unexplained by standard demographic characteristics. To assess the behavioral impact of imprecise beliefs, we ask beliefs about future outcomes under hypothetical scenarios that feature different levels of protective behaviors. We find that individuals who expect protective behaviors to reduce not only the subjective probability of a negative health outcome, but also the degree of imprecision associated with it, behave more protectively.