Periodical Directories

Impact factors can be calculated in various ways. The easiest way to do this is to take a database that includes citations (see Cited Reference Searching for a list of databases), divide the number of times a journal is cited (in a particular year or range of years) by the number of articles published in that journal for that time period, and the resulting quotient is the impact factor. It is somewhat more complex than this, but these are the basics.