The bibliometric behaviour of an expanding specialisation of medical research

This study investigates macular disease research and cataract research, which are both specialisations of Ophthalmology. Macular disease and cataracts are amongst the three leading causes of blindness in the world. Macular research expanded between 1992 and 2006 in that the proportion of Ophthalmology articles classified as macular increased by over 300% in that period. By contrast, during that same period the proportion of Ophthalmology articles classified as 'cataract' decreased by over 20%. This study investigates the bibliometric differences between the rapidly expanding specialisation of 'macular' and the slightly contracting specialisation of 'cataract'. Our rationale for investigating these bibliometric differences is that previous researchers have suggested that articles in expanding specialisations are likely to be more highly cited than articles in relatively static specialisations, and it seems important, when comparing specialisations, to try to ensure that articles in a relatively static specialisation are not penalised. This study first identifies substantial macro-level bibliometric differences between the two specialisations and then gauges the extent to which these differences were associated with the expansion of Macular compared with Cataract. The initial investigation uses coarse-grained delineations of the specialisation, formed from search terms frequently associated with macular (and cataract). It finds that articles in the relatively expanding specialisation were substantially more highly cited and that these differences were associated with the expansion of the specialisation rather than the size of the specialisation (the Matthew effect). A major limitation of this study is that its coarse-grained delineation of specialisations fails to identify substantial numbers of articles in the specialisation. A more fine-grained delineation using PubMed's Medical Subject Headings (MESH) has been piloted and additional articles identified. The use of MESH will be investigated further before the conference and our subsequent findings described in our conference presentation.