“…We assume that an observation is a vector of nominal values, V ij along distinct variables, A i . A measure of category utility (Gluck & Corter, 1985;Corter & Gluck, 1992), CU(C k ) = P(C k ) X i X j P(A i = V ij jC k ) 2 P(A i = V ij ) 2 ]; and/or variants have been used extensively by a system known as Cobweb (Fisher, 1987a) and many related systems (Gennari, Langley, & Fisher, 1989;McKusick & Thompson, 1990;Iba & Gennari, 1991;McKusick & Langley, 1991;Reich & Fenves, 1991;Biswas, Weinberg, & Li, 1994;De Alte Da Veiga, 1994;Kilander, 1994;Ketterlin, Gan carski, & Korczak, 1995). This measure rewards clusters, C k , that increase the predictability of variable values within C k (i.e., P(A i = V ij jC k )) relative to their predictability in the population as a whole (i.e., P(A i = V ij )).…”