This paper proposes an accessible measure of the relevance of additional terms to a given query, describes and comments on the steps leading to its develop-ment, and discusses its utility. The measure, termed relative query term rele-vance (RQTR), draws on techniques used in information retrieval, and can becombined with a technique used in creating corpora from the world wide web,namely keyword analysis. It is independent of reference corpora, and does notrequire knowledge of the number of (relevant) documents in the database. Although it does not make use of user/expert judgements of document relevance,it does allow for subjective decisions. However, subjective decisions are triangu-lated against two objective indicators: keyness and, mainly, RQTR.