Evaluating measures of combat deployment for U.S. Army personnel using various sources of administrative data.

Purpose: This study's purpose is to inform future research decisions about optimal measures for identifying combat deployments. We aim to evaluate four commonly utilized measures available in population-level administrative data to identify combat deployments in recent military operations among active duty Army personnel.

Methods: We compare these measures in three ways: (1) agreement (assessing the extent to which soldiers were differentially identified as combat deployed via each measure); (2) validity (calculating the sensitivity of each measure against a criterion measure); and (3) corroboration (examining how each measure predicted subsequent incidence of traumatic brain injury and post-traumatic stress disorder).

Results: We found that using personnel records to identify deployments to Iraq, Afghanistan, and/or Kuwait captured over 98% of combat-related deployments identified via self-reported measures. The addition of Kuwait allowed for detection of nearly 100% of battle injuries, improving sensitivity from 94.5% to 99.8%. However, self-reported combat exposure measures showed the largest differential in subsequent incidence of traumatic brain injury and post-traumatic stress disorder. Completeness and accuracy of different combat deployment measures varied significantly.

Conclusions: Using personnel records to identify deployment to Iraq, Afghanistan, and/or Kuwait was the most valid and comprehensive measure of combat deployment. However, self-reported combat exposure measures were more predictive of combat-related outcomes.