Subject specialties as interdisciplinary trading grounds: the case of the social sciences and humanities

In this study we explore the disciplinary diversity present within subject specialties in the social sciences and humanities. Subject specialties are operationalized as textually coherent clusters of documents. We apply topic modelling to textual information on the individual document level (titles and abstracts) to cluster a multilingual set of roughly 45,000 documents into subject specialties. The dataset includes the metadata of journal articles, conference proceedings, book chapters, and monographs. We make use of two indicators, namely, the organizational affiliation based on the departmental address of the authors and the cognitive orientation based on the disciplinary classifications at the publication level. First, we study the disciplinary diversity of the clusters by calculating a Hill-type diversity index. We draw an overall picture of the distribution of subject specialties over diversity scores and contrast the two indicators with each other. The goal is to discover whether some subject specialties are inherently multi- or interdisciplinary in nature, and whether the different indicators are telling a well-aligned, similar story. Second, for each cluster of documents we calculate the dominance, i.e. the relative size of the largest discipline. This proxy of disciplinary concentration gives an idea of the extent to which a specialty is disciplined. The results show that all subject specialties analyzed serve as interdisciplinary trading grounds, with outliers in both directions of the disciplinary-interdisciplinary continuum. For a large share of specialties, the dominant cognitive and organizational disciplinary classification were found to be well aligned. We present a typology of subject specialties by contrasting the organizational and cognitive diversity scores.