Association for Public Policy Analysis & Management

Background: The disciplinary structure of academia is very useful for assigning degrees, making hiring and promotion decisions, and evaluating scholarly output. This structure, however, becomes less valuable when individual disciplines lack the methods or other tools to single handedly address important problems. To address this shortfall of any single discipline, researchers, universities, and other institutions have encouraged discipline-spanning teams to bring their knowledge, methods, and experience to identify solutions to complex issues. For example, the NSF used to offer Integrative Graduate Education and Research Traineeship (IGERT) programs (e.g., Borrego and Newswander 2010; Moslemi et al. 2009; Schmidt et al. 2012) that specifically focused on training interdisciplinary researchers. The National Research Traineeship (NRT) programs (e.g., Liu 2017) took place of the IGERT grants, but the emphasis remains. Indeed, the NSF’s most recent emphasis on convergence continues this boundary spanning and integrative approach to research collaborations (Roco et al. 2013). At the university level, cluster-hiring practices attempt to facilitate cross-disciplinary collaborations among the new faculty.

Unfortunately, outcome data for researchers pursuing boundary-spanning research remains limited. Some evidence suggests that researchers who cut across disciplinary lines enjoy greater impact in their work (Leahey, Beckman, and Stanko 2017). Researchers with this entrepreneurial spirit need a broader skill set (National Research Council 2014) though they still take about the same amount of time to complete their degrees (Kniffin and Hanks 2017). Furthermore, these researchers run the risk of earning less in the first year after graduate school (Kniffin and Hanks 2017).

Data and Methods: Our objective is to add to this literature by expanding the work done in Kniffin and Hanks (2017). We will use the Survey of Earned Doctorates (SED), collected by the National Center for Science and Engineering Statistics (NCSES) to measure the rate at which newly minted PhDs declare interdisciplinary research and track this trend over time. Similar to Kniffin and Hanks (2017), we categorize a researcher as an interdisciplinarian if s/he declared more than one field on the SED. NCSES began asking this question in 2001 so we will track this proportion from 2001 through 2016. We expect that the increased emphasis on interdisciplinary research will lead to an increased rate over time. From the SED, we will also use reported expected salaries in the first year of employment after receiving the PhD to measure the impact of interdisciplinary research pursuits on near-term salary outcomes and whether this changes over time. We expect that the salary gap observed in for 2010 recipients (Kniffin and Hanks 2017) will close between interdisciplinary researchers and those who pursue single-discipline PhDs as the market responds to the increased demand for interdisciplinary researchers.

Results: Preliminary evidence shows an increasing trend in the rate at which PhD recipients declare a second field for their dissertation. In 2001, 24% of PhD recipients in the US answered this question affirmatively. In 2016, 44% did so. However, we observe a salary difference that persists over time between those who declare a second discipline and those who do not.