The sample of enlisted soldiers (9650 soldiers who attempted suicide and 153 528 control person-months) is a subset of the total sample (193 617 person-months) from the Army Study to Assess Risk and Resilience in Service members Historical Administrative Data Study. Standardized risk estimates (soldiers who attempted suicide per 100 000 person-years) assume other predictors were at their samplewide means. Estimates were calculated based on logistic regression models that included basic sociodemographic and service-related variables (sex, age at entry into the Army, current age, race/ethnicity, education, marital status, and time in service) and also included a dummy predictor variable for calendar month and year to control for secular trends.