Study Methodology

The Millennium Cohort Family Study is a critical component of the Millennium Cohort Program (MCP), the premier DoD research effort evaluating long-term military service effects on force readiness and national security.

The Family Study includes spouses of service members across all six military branches—Army, Navy, Air Force, Space Force, Marine Corps, and Coast Guard. Spouses become eligible through service members invited to participate in the Millennium Cohort Study.

Since its inception in 2001, the Millennium Cohort Study has enrolled five panels of service members. The Family Study, launched in 2011, has two enrollment waves:

• ✔ Panel 1 (2011): Nearly 10,000 military spouses
• ✔ Panel 2 (2020): Over 18,000 military spouses

Participants are randomly selected using DoD service records to ensure representation of warfighters and their families. Surveys are administered every three years for up to 21 years for spouses and 67 years for service members. The study follows spouses even if their military partner separates from service or their relationship status changes.