This dissertation employs modern psychometric techniques to estimate the item characteristics of the Conditional Reasoning Test of Aggression (CRT-A) and three related subscales. Using a sample size of 5,511 respondents, this dissertation provides an accurate assessment of the capability of the CRT-A to measure latent aggression. Additionally, a differential item functioning analysis compares student and applied samples. Results suggest that 21 of the 22 CRT-A items work as intended for the measurement of aggression and all 22 of the CRT-A items are good indicators of their respective factor subscales. Information curves indicate that the CRT-A is best suited for use with individuals who are high on latent aggression.