Active duty
Active duty component service members (unlike service members in the Reserve components), are entitled to free (or nearly free) health care for the duration of their military service, the details of which are captured electronically in DMSS. The active duty component thus constitutes a cohort where health events can be assessed longitudinally with minimal ascertainment bias. Over half of the specimens in the DoDSR are traceable to service members who have been on active duty, and 75% of active duty service members have provided three or more longitudinal specimens.