Research provided information about the magnitude of an individual's enlistment probability and how that probability depends on his personal characteristics, family background, employment situation, and expectations for further education. Analysis focused on male high school seniors and high school graduates. Findings suggested that each segment contains important subsegments defined by the individual's expectations for further education. Graduates were more responsive to work-related variables; seniors were more affected by education-related variables. The responsiveness to each variable often differed significantly across the subsegments defined by educational expectations. Findings permitted prediction of the enlistment probability of each individual in the sample, given his personal characteristics. These predicted probabilities showed that large relative differences can be discerned in the enlistment probabilities of young men with diverse characteristics. Findings were recommended to aid recruiters in evaluating the likely payoff from different segments and subsegments of their recruiting markets. The findings suggested that changes in the economic environment will influence different subsegments of the recruiting market differently and that in most segments the decision to enlist is not related to family income. Implications were reported for the design of aggregate data models for analyzing and forecasting enlistments and for expanded use of microlevel enlistment models. (YLB)