Are trivial risks the greatest risks of all?

Studies by Sjöberg published in 1999 (Journal of Risk Research), Volume 2, Number 2, pp. 129-49) have led him to conclude that perceived risk is mostly determined by probability of harm, whereas risk reduction demands are mostly determined by severity of harm and not probability. As a result, he finds that perceived risk does not predict demand for mitigation, leading him to question the value of the perceived risk construct. Sjöberg's results conflict with an extensive literature demonstrating (a) that protective behaviours are influenced by both probability and severity of harm and (b) that perceived risk is a strong predictor of desire for risk reduction. Why do Sjöberg's results conflict with this literature? The answer is to be found in the idiosyncrasies of his research designs and interpretations. In Study 1, Sjöberg asked people to judge the risk of adverse and sometimes trivial outcomes, leading his respondents to think of risk as the probability of those outcomes. In Study 2, he asked people to evaluate insurance against relatively probable losses, failing to test the hypothesis that probability thresholds trigger insurance purchases. Sjöberg's conclusions are thus misleading. For the purpose of understanding and predicting people's concerns, their desires for risk reduction, and their protective behaviours, it would be unwise to discard the concept of perceived risk.