How is credit for group work allocated when individual contributions are not observed? I use data on academics’ publication records to test whether demographic traits like gender influence how credit allocated under such uncertainty. While solo-authored papers send a clear signal about ability, coauthored papers are noisy, providing no specific information about each contributor’s skills. I find that men are tenured at roughly the same rate regardless of coauthoring choices. Women, however, are less likely to receive tenure the more they coauthor. The result is much less pronounced among women who coauthor with other women.