Eliminating the effects of reporting bias on risk perception.

Taking the public discourse on health risks due to aluminum in antiperspirants as an example, we conducted a randomized controlled study with repeated measurements to research how selective reporting of risk information affects risk perception and trust in risk information. First, the study varied the information scope that the experimental subjects received (selective vs. complete information). Selective information highlighted that a health risk is given. Considering the full range of studies, complete information is indicated the opposite. A second variation referred to the facticity of the hazardous agent mentioned in the risk information (a reference to either an actual or fictitious agent). Moreover, the selectively informed subjects received the complete information after the effects of the selective information were measured. Four risk perceptions constructs were chosen as dependent variables, differing on two dimensions (affective vs. cognitive and personal risk vs. risk for others). In addition, subjects´ trust in the given risk information was measured. The study reveals that presenting selective information amplifies risk perceptions. The effect was observed, irrespective of whether the hazardous agent mentioned in the risk information was actual or fictitious. When subjects who first received the selective information obtained the complete information, indicating no elevated risk, risk perceptions decreased. However, the analysis also indicates that corrective information (indicating no risk) is less trusted than selective information that points to health risks. Furthermore, proper toxicological understanding, i.e., taking into account the dose-response relationship, supports the effect of corrective information on risk perceptions.