RESPONSE BIAS - CHARACTERISTICS OF DETECTION THEORY, THRESHOLD THEORY, AND NONPARAMETRIC INDEXES

Models of discrimination based on statistical decision theory distinguish sensitivity (the ability of an observer to reflect a stimulus-response correspondence defined by the experimenter) from response bias (the tendency to favor 1 response over others). Measures of response bias have received less attention than those of sensitivity. Bias measures are classified here according to 2 characteristics. First, the distributions assumed or implied to underlie the observer's decision may be normal, logistic, or rectangular. Second, the bias index may measure criterion location, criterion location relative to sensitivity, or likelihood ratio. Both parametric and "nonparametric" indexes are classified in this manner. The various bias statistics are compared on pragmatic and theoretical grounds, and it is concluded that criterion location measures have many advantages in empirical work.