The classification of biomedical journals by research level

A new method of classification of biomedical research journals by research level (RL) into clinical or basic, or somewhere in between, is described that updates the system developed by CHI Research Inc. nearly 30 years ago. It is based on counting articles that have one of about 100 “clinical” title words, or one of a similar number of “basic” title words, or both. It allows over 3000 journals in the Science Citation Index (or other databases) to be classified rapidly and transparently, for changes in their research level with time, and for many individual papers in “mixed” journals to be categorised as clinical or basic. This revised version was published online in June 2006 with corrections to the Cover Date.