The minimax problem states that optimal construct organization involves two limiting levels of "too many" and "too few" available construct, dimensions for flexible, accurate discrimination of interpersonal events. Measures of thought disorder derived from personal construct theory, such as the Bannister-Fransella Grid, detect only "too many" constructs. The present study (N = 60) hypothesized that Ss with the least and most number of Functionally Independent Constructs (FIC) would evidence more thinking errors characteristic of a schizophrenic thought disorder than would Ss between the minimum and maximum groups. A grid form of the Role Construct Repertory Technique and the Whitaker Index of Schizophrenic Thinking (WIST; Forms A & B) were administered to 60 psychiatric inpatients. FIC scores were used to assign the Ss to five levels of construct organization and WIST scores served as the dependent variable. Two WIST scores confirmed the experimental hypothesis.