Measuring information through topical subheadings of the Medline database: a case study

Abstract

A method is described for measuring research information from thematic references such as headings and subheadings, reflecting different aspects using the Rasch model as the measuring instrument. The information utilised was obtained from the Medline database, searching the journal Anesthesiology, as a case for study, for topical subheadings from 1976 to 1995. An analysis is given of the research information based on 8,069 records. The type of information underlying (or latent in) topical subheadings goes beyond the basic information which is retrieved from the literature, and is measurable as a latent variable in the Rasch model. A measure was obtained for all the topical subheadings referred to by research papers in the journal. Simultaneously, the analysis provides measures for each year, as well as a description of the research trends in the anaesthesiology field. Drug effects had the highest measure of the subheadings searched, followed by pharmacology. The year 1994 accounted for most subheadings and 1978 for the fewest. Pharmacokinetics, epidemiology, ultrasonography, methods, physiology, manpower, supply and distribution, 1992 and 1995 were the misfitting subheadings and years. 50 1 2

What is wrong with obsolescence?

“…Like any other variable, “topicality” is conceived of as a directed line along which the items (years) and journals are situated (Alvarez & Pulgarín, 1996, 1999). One assumes there is a single direction that implies “more” of the variable.…”