Related Experiment Video
Updated: Jul 11, 2026

Inverse Probability of Treatment Weighting (Propensity Score) using the Military Health System Data Repository and National Death Index
Published on: January 8, 2020
U.S. military deployment during 2001-2006: comparison of subjective and objective data sources in a large prospective
Besa Smith1, Deborah L Wingard, Margaret A K Ryan
1Department of Defense Center for Deployment Health Research, Naval Health Research Center, San Diego, CA 92186-5122, USA. Besa@nhrc.navy.mil
Purpose:
Studies researching service members' health after deployment have relied on self-reported deployment history, although validity of these data remains unknown. This study compared self-reported and electronic deployment data and explored differences in functional health.
Methods:
Self-reported and military deployment data were compared for more than 51,000 participants enrolled in the Millennium Cohort Study (2004-2006). Kappa statistics were used to measure agreement. Analysis of variance was used to assess functional health, as measured by the Medical Outcomes Study Short Form 36-Item Health Survey for Veterans (SF-36V).
Results:
Of 51,741 participants who completed the initial deployment question, objective records and self-report agreed in 47,355 (92%). Agreement was substantial for deployment status, frequency, and number of deployments (kappa = 0.81, 0.71, and 0.61, respectively). Deployment start dates agreed within 1 month for 82% of participants confirmed as deployed once. Participants' Mental and Physical Component Summary scores from the SF-36V did not differ by agreement level.
Conclusions:
These findings indicate substantial agreement between self-reported and objective deployment information and no clinically meaningful differences in functional health for the small proportion with inconsistent deployment information. These findings should be reassuring to investigators who examine military deployment as a determinant of future health.
Related Concept Videos
Observational Studies
There are three types of observational studies – Prospective, retrospective, and cross-sectional.
Prospective Study
Prospective studies, also known as longitudinal or cohort studies, are carried out by collecting future data from groups sharing similar characteristics. One example of...
Data Collection by Observations
An astronomer viewing the motion and brightness of stars in the sky and recording the data is an example of observational data collection. A botanist recording...
Surveys
Data Collection I
Bias in Epidemiological Studies
Bioavailability Study Design: Healthy Subjects Versus Patients
