Deploying the Substitutive and Complementary Approaches to Enhance Predictions of Health Behaviour in Health Economics: A Quantitative Study

<b>Introduction:</b> The standard approach to predicting health behaviour in health economics depends on the deployment of expected utility as a predictor. However, this standard approach only explains limited variance in health behaviour, prompting the proposition of the substitutive and complementary approaches. Until now, both approaches have not yet been empirically examined. Hence, this study explores whether the substitutive and complementary approaches enhance predictions of health behaviour compared to the standard approach. <b>Methods:</b> Questionnaires were administered online to a panel of Dutch citizens (N = 2550). The questionnaire consisted of items on sample characteristics and instruments on expected utility, experienced utility, projected utility, and health behaviour. Data were analysed using descriptive, reliability, validity, and model statistics. <b>Results:</b> The findings of this study suggest that the standard approach explains only limited variance in health behaviour (R² = 0.27). The findings of this study also suggest that the substitutive approach (R² = 0.35-0.42) and complementary approach (R² = 0.38-0.43) explain more variance in health behaviour than the standard approach. The findings of this study further suggest that there are no discernible differences between the substitutive and complementary approaches to predicting health behaviour in health economics. <b>Conclusions:</b> Predictive enhancement of the standard approach can be established by applying the substitutive or complementary approach. However, within these approaches, different configurations of predictors might be selected based on different perspectives. Although perspectives may vary, projected utility has a particularly strong effect on and explained variance in health behaviour, which may be especially useful for improving health policies.