RAND Report Examines Ways to Compare the U.S. Army's Suicide Rate with the General U.S. Population

For Release

March 13, 2020

The U.S. Army should use an expanded set of demographic factors when comparing suicide rates to those in the general population to get a more accurate comparison, according to a new report from the RAND Corporation.

Over the past 15 years, the suicide rate among members of the U.S. Armed Forces has doubled, with a significant number observed among soldiers in the Army. More than 100 active duty Army soldiers have committed suicide over the past three years, or about 25 for every 100,000 people. At the same time, the suicide rate among the general U.S. population has seen a parallel, albeit smaller, increase across genders and age groups in nearly every state: about 40,000 people commit suicide each year, or about 13 for every 100,000.

In the past, the Army attempted to compare the two groups by standardizing the general population to look like the military population on demographic characteristics, such as age and gender. However, given the rise in suicide rates over the past decade the Army wanted to better understand whether standardization based solely on age and gender is enough.

Being able to accurately compare the two populations can potentially help the Army gain a better understanding of suicide trends and identify strategies that prevent suicide among its soldiers.

“If the goal is to determine whether suicide risk is higher or lower for soldiers than it would have been if they hadn't joined the Army, then you have to control for the fact that people who join the Army look substantially different on a multitude of factors from the general population, even before they joined,” said Beth Ann Griffin, lead author of the study and a senior statistician with nonprofit, nonpartisan RAND.

“The preferred comparison would be the one that includes factors that are associated with suicide risk, differ between military and the general population, and are outside the control of the Army. Here, we show how sensitive the comparisons can be to a small set of factors, with the important caveat that even the comparisons shown are subject to bias because we cannot fully match the Army to the general U.S. population on all known and unknown risk factors for suicide.”

By using an expanded set of six factors—gender, age, time of year/seasonality, race/ethnicity, marital status and educational attainment—the RAND study found the expected rate of suicide in the subset of the general U.S. population that “looks like” the Army population is consistently lower than when the expected rate is constructed adjusting for age and gender only. Marital status was the key factor in driving this shift.

The RAND study also found several Army-relevant factors that affect suicide risk in the Army—such as deployment history, unit location, rank and military occupation—that were not matchable with comparable data from the U.S. general population. It is likely that the difference between the Army and general population suicide rates will vary as a function of these unmatchable factors, though it is unclear by how much.

Ideally, the comparison would include additional factors such as occupation, mental health and gun ownership, but data on these factors are not as readily available for both populations. As such, Griffin and her colleagues recommend that the Army collaborate with the U.S. Census Bureau, the Centers for Disease Control and Prevention and the Department of Labor to improve occupation/industry coding for general U.S. population deaths. And because soldiers may differ from their general population counterparts regarding ownership of or access to personally owned firearms—the suicide method used in the majority of Army suicides—the Army also should seek voluntarily provided data on soldiers who own personal firearms and should encourage the CDC or other federal agency to resume collecting voluntarily provided survey data on gun ownership and use in the general population, according to the report.

Future research should examine the suicide risk among those with mental health diagnoses in the Army relative to similar individuals in the general U.S. population, the researchers conclude.

Other authors of the study, “Comparing the Army's Suicide Rate with the General U.S. Population: Identifying Suitable Characteristics, Data Sources and Analytic Approaches,” are Geoffrey E. Grimm, Rosanna Smart, Rajeev Ramchand, Lisa H. Jaycox, Lynsay Ayer, Erin Leidy, Steven Davenport, Terry L. Schell, and Andrew Morral.

Research for the study was conducted within RAND Arroyo Center's Personnel, Training and Health Program. RAND Arroyo Center, part of the RAND Corporation, is a federally funded research and development center sponsored by the United States Army.

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