Explaining Differences in Predicted O-5 Promotion Outcomes by Race/Ethnicity and Sex Among Navy Officers

The U.S. Department of the Navy desires to better understand the drivers of differences in officer retention and promotion across demographic groups. This Institute for Defense Analyses research identifies the differences in predicted O-5 promotion outcomes across race/ethnicity and sex groups of Navy line officers commissioned as O-1s in 2001-2018. Using administrative military personnel data, we train two machine learning (ML) models: one predicts retention, the other predicts promotion. We calculate the effect of each feature on an individuals likelihood of retention or promotion, and compare across demographics to identify differences in which and how much features matter. We find that officer subspecialty and, to some extent, qualification designations matter more for female and minority retention than for White males, while officer primary designator consistently matters more for retention among White males. In the promotion model, officer subspecialty is especially influential for female and minority promotion outcomes, while officer primary designator has mixed importance across demographics, suggesting primary designator is less important than subspecialty to promotion. Notably, conditional on serving ten years in the Navy, number of dependents is no more consequential for female retention than for White males, suggesting that childbearing may not drive differential female attrition as some have postulated.