A new approach to defining a multidisciplinary field of science: The case of cardiovascular biology

This paper describes a new and objective method for tackling the problem of defining a multidisciplinary research area for bibliometric analysis. The test field was cardiovascular biology. A three stage process was adopted in setting a boundary around this research field:

1. Appropriate sections of a hierarchical subject classification scheme, Medical Subject Headings (MeSH), were developed into a “MeSH filter” through which papers indexed in MEDLINE were screened.
2. A panel of cardiovascular experts reviewed the core set of classification terms, identifying irrelevant and missing areas, facilitating the development of a more sophisticated “filter”.
3. The definition was validated using publication lists from research departments with a known interest in cardiovascular research.

This iterative process resulted in a definition of the field which captured basic and clinical research papers from the international biomedical research community and which was recognisable to experts in the field of cardiovascular research. Importantly, the field boundary also excluded publications which were not relevant to cardiovascular research. The process of involving experts in shaping the field definition also yielded two intangible, but key benefits: (a) it lent credibility to subsequent analyses, the results of which were to be presented to policy-makers in cardiovascular biology, and (b) it served to shape consensus among the cardiovascular experts on the full range of scientific disciplines that are relevant to their field. Analysis of international publishing in cardiovascular research revealed that whilst the UK and US dominate in total numbers of papers, the relative emphasis on cardiovascular research in these countries (as a proportion ofall biomedical publishing) is actually quite low, and declining. Japan and Germany in contrast appear to give greater emphasis to cardiovascular research in their national portfolios of biomedical science, and between 1988–1991 Japan established a marked increase in activity.