Judging risks and benefits in the small and in the large

Abstract Between April 1978 and October 1979 a large psychometric field study on personal judgments of divergent risky activities was carried out in and around the greater Rotterdam harbor area. Almost 700 adult women and men from three different age groups, and living at systematically varying distances from an area of heavy industries, were personally interviewed with the help of various psychometric judgment tasks. Here, a brief review is given of a theoretical scheme of “aspects of risky decision problems” underlying this empirical study. An account is given of the plan and methods for data collection and analysis. Multidimensional scaling analyses are reported which have resulted in three pairs of cognitive dimensions underlying sets of individual judgments of the “riskiness,” “beneficiality,” and “acceptability,” respectively, of a basic collection of 26 risky activities. “Riskiness,” for example, seems to have been conceptualized as depending upon the “size of potential accident” and the “degree of organized safety.” The various cognitive dimensions appeared to have a particular pattern of intercorrelations, and their interpretations were supported by several aspects of risky decisions, which had been explicitly judged in separate tasks. Respondents disagreed about the implicit weight given to secondary dimensions of “riskiness,” “beneficiality,” and “acceptability.” This could, to some extent, be traced back to systematic differences in group characteristics. The existence of such disagreement implies that average personal judgments of risk, benefit, and acceptability should be handled with extreme caution. Contrary to a classical thesis of risk analysts, no relation was observed between judgments of overall riskiness and those of overall beneficiality across the set of 26 activities. Scale values of the activities on “beneficiality” dimensions did, however, strongly correlate with dimension values of “acceptability.” This suggests that “riskiness” plays a secondary role in risk acceptance decisions. Some implications for understanding societal risk debates, as well as a few weaknesses of this and other risk perception studies, are mentioned. We finally discuss why, and how, risk—benefit perception studies could usefully serve risky decision makers.