The Importance of the Data-generating Model in Probability Estimation.

by S. Lichtenstein, G. J. Feeney

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A demonstration that experimental subjects who appear to make very poor probability estimates may in fact be making careful and consistent estimates based on a different mental model of the situation than that used by the investigator. Of 11 male college students engaged in a 300trial probability estimation task involving hypothetical bombs aimed at hypothetical targets, nine gave estimates that compared very poorly with the "true" values calculated by the experimenters. Comments by the subjects led to a reanalysis of the data according to a different method of estimation. This showed that the responses were, in fact, accurate in terms of the subjects' implicit model of the situation. Care must be taken not to confuse a subject's accuracy in probability estimation tasks with his conceptual structuring of the problem. 14 pp. Refs.

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