Interdisciplinary Dissertation Research Among Public Health Doctoral Trainees, 2003-2015

Objectives: Given the call for more interdisciplinary research in public health, the objectives of this study were to (1) examine the correlates of interdisciplinary dissertation completion and (2) identify secondary fields most common among interdisciplinary public health graduates. Methods: We analyzed pooled cross-sectional data from 11 120 doctoral graduates in the Survey of Earned Doctorates, 2003-2015. The primary outcome was interdisciplinary dissertation completion. Covariates included primary public health field, sociodemographic characteristics, and institutional attributes. Results: From 2003 to 2015, a total of 4005 of 11 120 (36.0%) doctoral graduates in public health reported interdisciplinary dissertations, with significant increases observed in recent years. Compared with general public health graduates, graduates of environmental health (odds ratio [OR] = 1.74; P < .001) and health services administration (OR = 1.38; P < .001) doctoral programs were significantly more likely to report completing interdisciplinary dissertation work, whereas graduates from biostatistics (OR = 0.51; P < .001) and epidemiology (OR = 0.76; P < .001) were less likely to do so. Completing an interdisciplinary dissertation was associated with being male, a non-US citizen, a graduate of a private institution, and a graduate of an institution with high but not the highest level of research activity. Many secondary dissertation fields reported by interdisciplinary graduates included other public health fields. Conclusion: Although interdisciplinary dissertation research among doctoral graduates in public health has increased in recent years, such work is bounded in certain fields of public health and certain types of graduates and institutions. Academic administrators and other stakeholders may use these results to inform greater interdisciplinary activity during doctoral training and to evaluate current and future collaborations across departments or schools.