Absolute and Relative Biases in Estimations of Personal Risk1


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    This research was supported in part by Colby College Social Science Grants 01-2207 and 01-2230 to the second author. The authors are grateful to Victoria Cluck and Linette Kindred at Rutgers University and Colleen Burnham, Dorothy Evertsen, and the student assistant staff at Colby College for their assistance with data collection, and to two anonymous reviewers for their comments on an earlier version of this manuscript. Alexander Rothman is now at the University of Minnesota.

Correspondence concerning this article should be addressed to Neil D. Weinstein, Department of Human Ecology, Cook College, Rutgers University, P.O. Box 231, New Brunswick, NJ 08903. e-mail: weinsteinc@aesop.rutgers.edu.


Two studies examined the accuracy of personal risk estimates, as determined by comparing mean estimates made by college students with population statistics for college-educated individuals. Study 1 suggested that optimistic biases (the tendency for people to think they are less at risk than the average person) arise more because people overestimating the average person's risk than because they underestimate their own risk. In Study 2, subjects rated their risk after being presented with risk statistics that were 150%, 100%, or 50% of the true values. Subjects' estimates decreased with decreases in the comparison statistics, as if subjects attempted to preserve their “below-average” status, but they changed less than did the statistics and were actually pessimistic in comparison to the 50% values. Implications for interventions designed to influence risk perceptions are discussed.