Standing Tall: Do Height-Based Accountability Incentives Predict Artificial Increases in Measured Height Among...

The objective of this study was to investigate the changes in men's and women's measured height in response to weight gain above standards for the U.S. Navy and to quantify associated distortions in body mass index (BMI). We expected that some servicemembers would manipulate their measured height to comply with service standards.

The study was a retrospective observational study. The data were housed in the Person-Event Data Environment, an individual-level administrative registry from the United States Department of Defense. All participants were active-duty U.S. Navy sailors aged 21-50 during the years 2010-2019. The main outcomes were height and weight as recorded during twice-yearly physical fitness assessments and BMI calculated as: height in pounds × 703/(height in inches)2. We assessed whether weight gain above standards was associated with an increase in height at the subsequent height-weight assessment.

Among the 489,020 sailors, individuals were nearly 1.5 times as likely to measure taller when they gained weight that put them above military height-weight standards as compared to those who continued to remain within standards. Men were more often out of standards and therefore their measured height increased during subsequent assessments more often than women. Increases in height depressed measures of BMI slightly.

Among U.S. sailors, taller height was correlated with surpassing height-based weight limits, where taller individuals were allowed to weigh more and still meet professional weight standards. Results underscore that current height-weight accountability standards may distort behavior, leading servicemembers to manipulate measurements rather than improve job-relevant fitness. Instead, greater reliance on fitness-based measures of health, such as fitness tests, may hold promise for upholding servicemember readiness. Our results highlight that when stakes are attached to a measure, individuals may work to raise their performance using strategies that are misaligned with the policy intent.