Reference letters play an important role for both postgraduate residency applications and medical faculty hiring processes. This study seeks to characterise the ways in which gender bias may manifest in the language of reference letters in academic medicine. In particular, we conducted a systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched Embase, MEDLINE and PsycINFO from database inception to July 2020 for original studies that assessed gendered language in medical reference letters for residency applications and medical faculty hiring. A total of 16 studies, involving 12 738 letters of recommendation written for 7074 applicants, were included. A total of 32% of applicants were women. There were significant differences in how women were described in reference letters. A total of 64% (7/11) studies found a significant difference in gendered adjectives between men and women. Among the 7 studies, a total of 86% (6/7) noted that women applicants were more likely to be described using communal adjectives, such as “delightful” or “compassionate”, while men applicants were more likely to be described using agentic adjectives, such as “leader” or “exceptional”. Several studies noted that reference letters for women applicants had more frequent use of doubt raisers and mentions of applicant personal life and/or physical appearance. Only one study assessed the outcome of gendered language on application success, noting a higher residency match rate for men applicants. Reference letters within medicine and medical education exhibit language discrepancies between men and women applicants, which may contribute to gender bias against women in medicine.
