Which medical journals have the greatest impact?

High-impact medical journals are identified using data from the 1981 and 1982 Journal Citation Reports. The Journal Citation Reports are an annual supplement to the Science Citation Index. Journals publish different types of editorial matter, much of which does not report substantive research. A special algorithm is used to calculate the number of substantial or "meaty" items. In 1981 The Lancet and The New England Journal of Medicine ranked highest among 78 journals in citations received; 53,945 and 47,887, respectively. These journals also have the highest impact factor, the average number of citations received by items in a journal's 1980 and 1981 issues. The British Medical Journal was highest in 1981 immediacy index, the measure of how quickly a journal's 1981 items were cited in 1981.