A brief review of the rich heritage of classifications and terminologies is the background for a description of the Mayo Clinic's clinical terminology development. Vender specific system constraints prompted the scope and style of an interim problem list vocabulary. We describe the sources and review process which led to a working terminology for use in a Computer-based Patient Record (CPR). Because terminology development is often subjective and metrics against which to measure the quality of individual human judgements are few, we decided to compare the selection of preferred terms made by general internists with those made by sub-specialists. A significant difference between a sub-specialist's assignment of preferred terms and a general internist's (948 vs. 2271, P < 0.001) was observed. Sub-specialists were less than half as likely as a generalist to designate a term as a preferred form. These results emphasize the need for sub-specialty editing when assigning preferred terms to concepts.