This is an empirical study to discriminate between troublemakers and nontroublemakers in a prison population by means of statistical analysis of individual test scores obtained from the use of the Minnesota Multiphasic Personality Inventory, the Stanford Achievement Test, and the Otis Test of Mental Ability. The sample upon which this investigation was made consisted of 112 matched pairs of troublemakers and nontroublemakers, all inmates of the Texas Prison System. They were matched on the following items: age, race and sex, length of sentence, type of crime, and number of former commitments. The two groups were compared on twelve factors of the MMPI, obtained intelligence quotients as measured by the Otis Test of Mental Ability, and Educational Achievement as obtained through applications of the new Stanford Achievement Test. [...]