Objective.  Risk perceptions play a pivotal role in health behaviour theories. Accurate measurement is essential in order to investigate the explanatory value and effectiveness of interventions influencing these beliefs. This study investigated the reliability and predictive validity of different risk perception operationalizations related to skin cancer and sunscreen use in order to explain the inconsistent findings in literature regarding the relationship between risk perceptions and (cancer related) behaviours.

Design and methods.  Two on-line surveys were conducted. Study 1 (N= 175) was conducted among university students to investigate the test–retest reliability of different operationalizations of perceived likelihood and perceived severity and to assess their correlations with sunscreen use. Study 2 (N= 418) was a prospective study among Dutch adults and assessed longitudinal correlations between the different operationalizations and sunscreen use.

Results.  Internal consistency (alpha) ranged between .13 and .90 for likelihood measures and between .37 and .88 for severity measures. Test–retest correlations (r/ICC) ranged between .51 and .82 for the likelihood measures and between .58 and .75 for the severity measures. Conditional likelihood estimates, particularly when phrased affectively (feeling at risk), and comparative severity questions were the strongest correlates of behaviour.

Conclusion.  Conditional likelihood and comparative severity might be better predictors of health behaviour than commonly used operationalizations of risk perception. These measures may be relevant for use in the development and evaluation of intervention programmes, and should be acknowledged by health behaviour theories. Suggestions for future research are discussed.