Deploying projected utility to predict health behaviour in health economics: a quantitative study.

Expected utility is increasingly deployed as a predictor of health behaviour within the broader domain of health economics and health sciences in general. However, research shows that this concept only explains limited variance in health behaviour. This limited explained variance is often attributed to the questionable theoretical axioms underlying the concept. Due to these limitations it was hypothesised that the concept of utility should not be conceptualized in terms of preferences for future health states (expected utility), but as realistic approximations of future health states (projected utility). Therefore, this study examines whether deployment of projected utility separately or in combination with expected utility enhances predictions of health behaviour as compared to expected utility. Online questionnaires were disseminated among a nationally representative panel of Dutch citizens (N = 2,550). The questionnaire encompassed items capturing demographic characteristics alongside instruments measuring expected utility, projected utility and health behaviour. Data analysis entailed descriptive, reliability, validity and model statistics. The results suggest that projected utility has a larger significant direct effect on and explains more variance in health behaviour than expected utility. The results subsequently indicate that expected utility and projected utility combined have a larger significant direct effect on and explain more variance in health behaviour than each type of utility separately. Health economists, policy makers and other public health practitioners are well advised to at least consider the separate or even combined deployment of projected utility in health economics in order to enhance predictions of health behaviour.