Countering demand for ineffective health remedies: Do consumers respond to risks, lack of benefits, or both?

Abstract

Objective We tested whether targeting the illusion of causality and/or misperceptions about health risks had the potential to reduce consumer demand for an ineffective health remedy (multivitamin supplements). Design We adopted a 2 (contingency information: no/yes) × 2 (fear appeal: no/yes) factorial design, with willingness-to-pay as the dependent variable. The contingency information specified, in table format, the number of people reporting a benefit vs. no benefit from both multivitamins and placebo, plus a causal explanation for lack of efficacy over placebo. The fear appeal involved a summary of clinical-trial results that indicated multivitamins can cause health harms. The control condition received only irrelevant information. Main outcome measure Experimental auctions measured people’s willingness-to-pay for multivitamins. Experiment 1 (N = 260) elicited hypothetical willingness-to-pay online. Experiment 2 (N = 207) elicited incentivised willingness-to-pay in the laboratory. Results Compared to a control group, we found independent effects of contingency information (-22%) and the fear appeal (-32%) on willingness-to-pay. The combination of both interventions had the greatest impact (-50%) on willingness-to-pay. Conclusion We found evidence that consumer choices are influenced by both perceptions of efficacy and risk. The combination of both elements can provide additive effects that appear superior to either approach alone.