Do local citation patterns support use of the impact factor for collection development?

The Impact Factor and Collection Development The journal impact factor (IF) is reported by ISI in Journal Citation Reports (JCR). “A journal's impact factor is based on 2 elements: the numerator, which is the number of citations in the current year to any items published in a journal in the previous 2 years, and the denominator, which is the number of substantive articles (source items) published in the same 2 years” [1]. Much research has been done on IF as a measure of local journal use for collection development. Blecic used a comparison of three methods: in-house use, circulation, and citation to determine journal use, finding a “significant correlation” between the three methods and arguing that because of this correlation, only one type of data was necessary to make retention decisions [2]. MacDonald's study of online journal usage in relation to citation analysis examined whether online journal use (as measured by an academic library) and a library's publisher-reported full-text downloads predicted citations, finding that “citation is clearly related to usage” [3]. Using Biosis Previews, Davis identified core journals in the life sciences by analyzing the journals in which Cornell University authors published [4]. Davis concluded that the “generic metrics of the JCR simply cannot provide the campus-level data crucial to making informed decisions about the local importance of individual titles,” as argued earlier by Pan [5] and Chrzastowski [6].