How research becomes knowledge in radiology: an analysis of citations to published papers.

The process by which research becomes generally disseminated knowledge in radiology was studied by an analysis of reference citations. A citation is the event that occurs when one paper is listed as a reference by another paper. Analysis of the citations received by 30 diagnostic radiology journals in 1985 showed that five journals received 73% of the citations. Approximately half of the citations were made to papers over 5 years old. Analysis of the citations received by the 1977 issues of eight journals over a 9-year period showed a rapid rise in the number of citations received, a peak in the third year after publication, and a slow, exponential decline. Analysis of citations to a group of individual papers showed that 10% of the papers received nearly 50% of the citations. This information suggests that citations to the radiology literature are concentrated among a handful of papers in a few journals. The citation activities of individual journals reflect in part their editorial policies. Parameters of citation activity may be relevant to selecting journals for subscription, reading, or publication. The radiology literature has lasting relevance and receives citations for many years. Advancement of the science of radiology follows the lead of a very few works; the most frequently cited papers concern practical techniques and procedures.