Trends in Interdisciplinary Dissertation Research: An Analysis of the Survey of Earned Doctorates
Summary and Conclusions
This working paper summarizes the trends in the reporting of interdisciplinary dissertation research, as measured by an indicator contained in the Survey of Earned Doctorates. This survey provides us with the best opportunity to examine the prevalence of interdisciplinary research among individuals earning doctoral degrees in the United States. No other existing data source provides such a comprehensive representation of doctoral graduates, making this examination of trends from the Survey of Earned Doctorates a valuable insight into the current status of interdisciplinary research.
The analyses contained in this report indicate that interdisciplinary research may be involved in a substantial proportion of doctoral dissertations. Twenty-eight percent of doctorate earners from 2001–08 reported using multiple fields of study in their dissertation research. This attests to the growing popularity and impact of the interdisciplinary movement.
The rate at which interdisciplinary dissertation research is conducted varied by field of study. That is, some fields of study were more likely than others to have individuals who report secondary fields of dissertation research. This suggests that certain disciplines are more encouraging of interdisciplinary research than others. Further examination of why researchers in some disciplines are more prone to conduct interdisciplinary research than in others would be useful in determining the contexts in which interdisciplinary research develops.
A majority of respondents who reported multiple research fields indicated two fields that are closely related to each other. Conversely, only about a third of interdisciplinary doctoral graduates reported using two fields that are more disparate. This is intriguing because some might argue that two fields must be unrelated in order for the research to be considered interdisciplinary. This trend suggests the need to further develop our understanding of the meaning of the term "interdisciplinary" and how these questions are interpreted by respondents.
We analyzed trends related to the change in question wording used in the Survey of Earned Doctorates. The wording change that occurred in the 2004 questionnaire did not result in any noticeable change in the overall rate at which doctoral recipients reported interdisciplinary research. However, when we looked at the rates by knowledge domain of respondents' primary field of study, we saw that the rate of interdisciplinary dissertations increased in many areas of study when the question wording changed. Furthermore, the rate at which individuals reported distantly related fields of study used in interdisciplinary dissertations increased dramatically with the change in the question wording. All of this suggests there is value in further examination of the meanings and interpretations given to these two questions. Millar and Dillman (2010) and Millar (2011) report the results of cognitive interviews that were designed to explore the meaning of the term "interdisciplinary" as used in the context of these questions and to evaluate the accuracy of these questions as indicators of interdisciplinary research.
Nevertheless, this introductory analysis of the data contained in the Survey of Earned Doctorates provides a useful starting point from which to further explore the development of interdisciplinary research from the perspective of individual researchers. These questions that we have analyzed as indicators of interdisciplinary research may be some of the only available indicators of this type of research available in existing data. This fact makes the Survey of Earned Doctorates and its follow-up, the Survey of Doctorate Recipients, valuable sources for analyzing the individual-level correlates and consequences of interdisciplinary research. Millar (2011) reports the results of the first analyses to use these data to examine the early career impacts of interdisciplinary research.