In the last two decades there have been studies claiming that science is becoming ever more interdisciplinary. However, the
evidence has been anecdotal or partial. Here we investigate how the degree of interdisciplinarity has changed between 1975
and 2005 over six research domains. To do so, we compute well-established bibliometric indicators alongside a new index of
interdisciplinarity (Integration score, aka Rao-Stirling diversity) and a science mapping visualization method. The results
attest to notable changes in research practices over this 30 year period, namely major increases in number of cited disciplines
and references per article (both show about 50% growth), and co-authors per article (about 75% growth). However, the new index
of interdisciplinarity only shows a modest increase (mostly around 5% growth). Science maps hint that this is because the
distribution of citations of an article remains mainly within neighboring disciplinary areas. These findings suggest that
science is indeed becoming more interdisciplinary, but in small steps — drawing mainly from neighboring fields and only modestly
increasing the connections to distant cognitive areas. The combination of metrics and overlay science maps provides general
benchmarks for future studies of interdisciplinary research characteristics.
We introduce an indicator to measure the diffusion of scientific research. Consistent with Stirling's 3-factor diversity model, the diffusion score captures not only variety and balance, but also disparity among citing article cohorts. We apply it to benchmark article samples from six 1995 Web of Science subject categories (SCs) to trace trends in knowledge diffusion over time since publication. Findings indicate that, for most SCs, diffusion scores steadily increase with time. Mathematics is an outlier. We employ a typology of citation trends among benchmark SCs and correlate this with diffusion scores. We also find that self-cites do not, in most cases, significantly influence diffusion scores.
Authors:Philip Shapira, Jan Youtie, and Alan Porter
This article examines the development of social science literature focused on the emerging area of nanotechnology. It is guided
by the exploratory proposition that early social science work on emerging technologies will draw on science and engineering
literature on the technology in question to frame its investigative activities, but as the technologies and societal investments
in them progress, social scientists will increasingly develop and draw on their own body of literature. To address this proposition
the authors create a database of nanotechnology-social science literature by merging articles from the Web of Science’s Social
Science Citation Index and Arts and Humanities Citation Index with articles from Scopus. The resulting database comprises
308 records. The findings suggest that there are multiple dimensions of cited literature and that social science citations
of other social scientists’ works have increased since 2005.
Authors:Alan Porter, Alex Cohen, J. David Roessner, and Marty Perreault
We offer two metrics that together help gauge how interdisciplinary a body of research is. Both draw upon Web of Knowledge
Subject Categories (SCs) as key units of analysis. We have assembled two substantial Web of Knowledge samples from which to
determine how closely individual SCs relate to each other. “Integration” measures the extent to which a research article cites
diverse SCs. “Specialization” considers the spread of SCs in which the body of research (e.g., the work of a given author
in a specified time period) is published. Pilot results for a sample of researchers show a surprising degree of interdisciplinarity.