This study explored the relationship between a new self-report measure built from justification mechanisms of aggression (i.e., the basis of conditional reasoning; James, 1998) with a traditional explicit measure and an implicit conditional reasoning measure of aggression. The construct validity and generalizability of the new measure were investigated by using non-work related criteria (violent acts, traffic violations, alcohol use, competitiveness, and agreeableness) in an undergraduate student sample. Correlations and moderated hierarchical multiple regressions were used to assess the relationships between variables. The results support the literature in that both explicit and implicit components of personality need to be examined. In conclusion, the newly developed measure fills a gap in the literature by operationalizing aggression as reasons for behaving aggressively. It is similar to the explicit aggression measure in that it is a self-report; however, the moderate correlation between the two suggests that each is measuring slightly different aspects of aggression.