Abstract Do men negatively respond when women first enter an occupation? We answer this question by studying the end of one of the final explicit occupational barriers to women in the United States: in 2016, the U.S. military opened all positions to women, including historically male-only combat occupations. We exploit the staggered integration of women into combat units to estimate the causal effects of the introduction of female colleagues on men’s job performance, behavior, and perceptions of workplace quality, using monthly administrative personnel records and rich survey responses. We find that integrating women into previously all-male units does not negatively affect men’s performance or behavioral outcomes, including retention, promotions, demotions, separations for misconduct, criminal investigations, and medical conditions. Most of our results are precise enough to rule out small detrimental effects. However, there is a wedge between men’s perceptions and performance. The integration of women causes a negative shift in male soldiers’ perceptions of workplace quality. The decline is driven by units integrated with female officers, likely arising from female officers increasing men’s awareness of workplace problems or from men’s dissatisfaction from working with women in positions of authority—even though men in such units show some performance gains. If male-dominated workplaces are reluctant to incorporate women due to expectations that men will become less productive, our paper provides evidence to weigh against that notion.

Internal labor markets are increasingly important for matching workers to jobs within organizations. We present evidence from a randomized trial that compares matching workers to jobs using the deferred acceptance (DA) algorithm to the traditional manager‐directed matching process. Our setting is the U.S. Army's internal labor market, which matches over 14,000 officers to units annually. We find that DA reduces administrative burden and increases match quality as measured by reduced justified envy, increased truthful preference reporting, and officers' and units' preferences over their matches. The overall impact of DA on officer retention and performance in the two years after officers started their new jobs is limited by strategic preference coordination between officers and units. However, DA leads to significant improvements in officer retention and promotions in markets with inexperienced managers. Our findings suggest that cross‐market communication between agents in internal labor markets can attenuate the benefits of strategyproof matching algorithms.