The Journal “Impact Factor”

The Institute for Scientific Information (ISI), a database publishing company that publishes Current Contents and Science Citation Index, has devised and promulgated what it terms the journal “impact factor.” ISI describes this factor as a “measure of the frequency with which the ‘average article’ in a journal has been cited in a particular year.” The factor is a ratio between citations and recent citable published items calculated by dividing the number of all current citations of items published in a journal during the preceding 2 years by the number of articles published in those 2 years by that journal. What, if anything, is wrong with the “impact factor”? There is absolutely nothing incorrect with the calculation of the ratio itself. However, the “impact factor” is misnamed and misleading. Being misnamed and misleading, the “impact factor” has been misused. It is being held out as a measure of the importance of a specific journal article and the journal in which the article appeared. By extension, the “impact factor” is also being misused to gauge the relative importance of individual researchers, research programs, and even the institution hosting the research. We recommend that the term “impact factor” be abolished and that this measure be renamed in keeping with its actual role, that merely of a time-specific “citation rate index” and nothing more. What is currently called the “impact factor” should not be misused to evaluate journals or to validate the scientific relevance of a particular researcher or research program, especially in decisions regarding employment, funding, and tenure.