[Evaluation of the scientific activity through bibliometric indices]

The scope of bibliometric studies is the treatment and quantitative analysis of scientific publications. They belong to the so-called "social studies of science", and science policy constitutes one of its main applied fields. These studies efficiently complement the opinions and judgements of experts, thus providing objective and useful tools for evaluating the results of scientific activity. Nevertheless, given the impact that these evaluations have on the assignment of funding for research and even on the professional career of investigators, it becomes essential to know in detail the characteristics of bibliometric indicators and the limitations of their use. The Science Citation Index database is one of the most employed. In the case of biomedical research it is useful to analyze the most internationally visible scientific production, since it satisfactorily covers biomedical journals; however, clinical research with local interest published in Spanish journals is not included in that database. Widely employed bibliometric indicators are those measuring scientific activity through the number of publications, those based on the citations received by published studies and, in between them, the impact of journals. The impact factor is an indicator very used in bibliometric studies; though occasionally a high impact factor is assumed to reflect high quality, this indicator specifically measures visibility and diffusion of the works published by these journals rather than their scientific quality.