title: On the analysis of psychometric functions: the Spearman-Kärber method.
abstract: With computer simulations, we examined the performance of the Spearman-Kärber method for analyzing psychometric functions and compared this method with the standard technique of probit analysis. The Spearman-Kärber method was found to be superior in most cases. It generally yielded less biased and less variable estimates of the location and dispersion of a psychometric function, and it provided more power to detect differences in these parameters across experimental conditions. Moreover, the Spearman-Kärber method provided information about the skewness and higher moments of psychometric functions that is beyond the scope of probit analysis. These advantages of the Spearman-Kärber method suggest that it should often be used in preference to probit analysis for the analysis of observed psychometric functions.
authors.affiliation: Department of Psychology, University of Otago, Dunedin, New Zealand. miller@otago.ac.nz
authors.forename: J
authors.initials: J
authors.lastname: Miller
authors.forename: R
authors.initials: R
authors.lastname: Ulrich
mesh_terms: D016001:Confidence Intervals; D006801:Humans; D011336:Probability; D011594:Psychometrics / Q000379:methods*; D011601:Psychophysics / Q000706:statistics & numerical data*; D012684:Sensory Thresholds; D018709:Statistics, Nonparametric