Unintended Consequences: An Analysis of the Impact of Increased Time-In-Service Promotion Requirements on NCO Retention and Performance in the USMC

Abstract

In 2019, the Marine Corps announced that the minimum required time-in-service and time-in-grade for promotion to sergeant and staff sergeant would increase in 2020. Since that policy was enacted, a 2,700-sergeant deficit has been identified. This study confirms that deficit is linked to the promotion policy change by estimating the impact of the increased promotion requirements on the retention and job performance of corporals and sergeants. To estimate the policy impact, I mimic an experimental research design and employ a difference-in-differences framework, comparing Marines in jobs where the average time to promote increased the most against Marines in jobs where promotion timing stayed the same or changed minimally. The results show that corporals in the treatment group were significantly more likely to separate after the new policy was enacted, while sergeants in the treatment group were less likely to separate. Additionally, corporals in the treatment group were more likely to be meritoriously promoted to sergeant after the new policy was in effect, though the effect of the policy on the performance of treated corporals was negligible. Based on these results, I recommend that the Marine Corps focus retention incentives and lateral entry initiatives towards military occupational specialties that have been most affected by this policy, as well as further evaluate meritorious promotion management to enhance its effectiveness in selecting individuals for early advancement.