Despite rhetoric supporting the advancement of women on corporate boards, meager evidence supports significant progress over the past decade in the United States. The authors examine archival board data (for more than 3,000 U.S. publicly traded firms) from 2002 to 2011 and find that a female is most likely to be appointed to a corporate board when a woman has just exited the position. A similar propensity occurs to reappoint a male when a man leaves, although the effect is smaller than for women. The authors argue that this “gender-matching heuristic” can impede progress in attaining gender diversity, regardless of intention, because it emphasizes the replacement of existing women rather than changing board composition. The authors replicate this effect in follow-up laboratory studies and show that “what works” to increase the representation of women on boards, irrespective of gender matching, is to increase the number of women in the candidate pool.