Classification of 'research letters' in general medical journals and its consequences in bibliometric research evaluation processes

This paper describes the results of classifying document types in various electronic representations of the same scientific literature. Research evaluation assessment procedures at the Leiden University Medical Centre have shown that the classifications of research letters in the highly prolific general medicine journals occurs in various ways, resulting in discrepancies in representation of these documents, these discrepancies create problems, if 'research letters' are classified sometimes as articles, or sometimes as letters. And although the representations of these documents in the citation indexes do vary with the original journal, the classification of research letters in the citation indexes follows certain specific guidelines that do right by the specific characteristics of these publications.