Mentored research experiences bridge the wealth gap in PhD admissions

<title>Abstract</title> <p>PhD admissions decide which aspiring researchers gain access to scientific careers. Socioeconomic background has long shaped academic opportunity, influencing entry into elite undergraduate institutions1–3 and the professorate4, yet its role in doctoral admissions has remained difficult to measure directly. Here we analyze 52,888 PhD applications submitted between 2013-2023 to one of the largest PhD-granting institutions in the United States, combining applicant credentials and recommendation letters with faculty evaluations and socioeconomic measures—including family home equity, parental education and reported financial hardship. We uncover a distinct wealth gap in doctoral admissions: applicants from higher socioeconomic backgrounds are both more likely to apply and to be admitted. Although faculty do not explicitly evaluate wealth, socioeconomic advantage systematically propagates through key admissions criteria including grades, test scores and undergraduate institutional prestige. In contrast, we find that mentored research experiences, and their resulting recommendations, provide an influential and wealth-agnostic signal of research potential. Expanding access to scientific training therefore calls for a stronger ecosystem of mentored research experiences, broader faculty participation in mentoring, and earlier encouragement for aspiring scholars to seek out these opportunities.</p>