From citation indexes to informetrics: Is the tail now wagging the dog?

This article provides a synoptic review and history of citation indexes and their evolution into research evaluation tools including a discussion of the use of bibliometric data for evaluating U.S. institutions (academic departments) by the National Research Council (NRC). The review covers the origin and uses of journal impact factors, validation studies of citation analysis, information retrieval and dissemination (current awareness), citation consciousness, historiography and science mapping, Citation Classics,(R) and the history of contemporary science. Retrieval of information by cited reference searching is illustrated, especially as it applies to avoiding duplicated research. The fifteen-year cumulative impacts of journals and the percentage of uncitedness, the emergence of scientometrics, old boy networks, and citation frequency distributions are discussed. The paper concludes with observations about the future of citation indexing.