The validity of an index measuring criminal dangerousness was further evaluated by determining whether it could discriminate among prisoners committing violent crimes at three levels of severity. The index score was a multiplicative product of an antisocially score and an IQ score, with high antisocially and low IQ reflecting greater dangerousness. Comparison of index scores for men committing murder (most severe); robbery and rape (intermediate severity); and assault, child molestation, and manslaughter (least severe) revealed a significant monotonic increase in dangerousness scores as increasingly severe crimes were considered. Several recommendations for the measurement of criminal dangerousness were offered.