The goal of the current research was to test whether direct versus indirect measures of comparative optimism yield different results as a function of health risk severity and prevalence. A random-digit sample of community residents (N = 259) responded to interview questions about perceived vulnerability using both direct (i.e. self-to-peer risk) and indirect comparison measures (i.e. separate questions about self and peer risk). Responses to direct comparison measures were more affected by prevalence, whereas indirect comparison measures were more affected by severity. These results may offer guidance to researchers and practitioners about when it may be more appropriate to use direct versus indirect measures of comparative health risk.