A method is described for measuring information from keywords, using the Rasch model as the measuring instrument. The information utilized was obtained from the Medline data base, searching the journal Diabetes for a set of keywords appearing in the diabetes field from 1974 to 1994. An analysis is given of the research in diabetes over the last 21 years based on the keyword information.
A measure was obtained for all the keywords considered, and the areas of research identified by the respective keywords were analyzed. At the same time, this analysis provided measures for each year, as well as a description of the "research trends" in diabetes. Insulin had the highest measure of the keywords searched, followed by Diabetes mellitus experimental.
The year 1991 accounted for most keywords and 1978 fewest. Diabetes mellitus noninsulin dependent, Diabetes mellitus experimental, and Diabetes ketoacidosis were the keywords that misfit the model, and 1974,1977, and 1991 were the misfitting years. The "information underlying keywords" is a latent variable, and the Rasch model is a useful instrument for measuring that variable. This methodology allows how research has been developing over the last 21 years to be described according to the keywords and their related fields.