Abstract
Two methods of estimating the value of populationd′ from a group of subjects were investigated to determine the conditions under which each would be the less biased estimator. The first method, calculatingd′ for each subject and then averaging the estimates, yields an estimate of populationd′ called averaged′. The second method requires that data from all subjects be pooled and then an estimate of populationd′ calculated. This estimator is called pooledd′. Monte Carlo simulations indicated that pooledd′ was the less biased estimator when the number of trials per subject was fairly low, whereas averaged′ was the less biased estimator when the number of trials per subject was fairly high. The crossover point at which averaged′ becomes less biased than pooledd′ is shown to depend on the value of populationd′, the average bias of subjects in the population, and also on the level of criterion variability within the population.
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Dorfman, D. D., &Berbaum, K. S. (1986). RSCORE-J: Pooled rating-method data: A computer program for analyzing pooled ROC curves.Behavior Research Methods, Instruments, & Computers,18, 452–462.
Goodman, L. A. (1970). The multivariate analysis of qualitative data: Interactions among multiple classifications.Journal of the American Statistical Association,65, 226–256.
Hautus, M. J. (1995). Corrections for extreme proportions and their biasing effects on estimated values ofd′.Behavior Research Methods, Instruments, & Computers,26, 46–51.
Macmillan, N. A., &Creelman, C. D. (1991).Detection theory: A user’s guide. Cambridge: Cambridge University Press.
Macmillan, N. A., &Kaplan, H. L. (1985). Detection theory analysis of group data: Estimating sensitivity from average hit and false-alarm rates.Psychological Bulletin,98, 185–199.
Snodgrass, J. G., &Corwin, J. (1988). Pragmatics of measuring recognition memory: Applications to dementia and amnesia.Journal of Experimental Psychology: General,117, 34–50.
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The author would like to thank John Irwin for comments made on an earlier draft of this manuscript, and Wayne Donaldson and Doris Aaronson for suggestions made during the review process.
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Hautus, M.J. Calculating estimates of sensitivity from group data: Pooled versus averaged estimators. Behavior Research Methods, Instruments, & Computers 29, 556–562 (1997). https://doi.org/10.3758/BF03210608
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DOI: https://doi.org/10.3758/BF03210608