Impact Factor Vs. Immediacy Index

• Impact Factor:

• Average number of times articles from the journal published in the past two years have been cited in the JCR year.

• Calculated by dividing the number of citations in the JCR year by the total number of articles published in the two previous years.

• Measures how often a typical article in a journal is used as a source by researchers

• Impact Factor of 10 means that articles are cited an average of 10 times

• Immediacy Index:

• Average number of times an article is cited in the year it is published.

• Indicates how quickly articles in a journal tend to be cited after publication

• Can eliminate bias of larger/more-established journals having more articles per issue as than new/smaller publications.

• May increase bias in favor of journals with more issues published in a year such as Science or NEJM.

• May favor articles published early in the year due to longer window of possible citations by researchers