This report analyzes the attrition of Army Reserve and Army National Guard enlistees who have had no prior military service. It develops models of attrition that assign a probability of attrition to each recruit type. The models are based on analyses of historical attrition for the fiscal year 1980-1982 cohorts entering the Army National Guard and Army Reserve. The report focuses on separations to civilian life and develops separate models for attrition during the training and posttraining periods and the first two years after enlistment. A major finding is that economic factors and institutional policies are extremely important determinants of attrition across different cohorts. Although it is possible to predict the relative attrition risk associated with changes in composition or quality, the predictive power of such models is not good. As much as possible, changes in component policies or training standards must be accounted for, as well as the effect of changing economic conditions on both the entering cohorts and the component.