Quantitative analysis of journals is a way traditional peer review may be augmented to gain a more complete picture of a scholar's impact in a particular field. Three measures can be used:
Knowing the impact or importance of the journal can help in making strategic decisions about where an author will choose to submit an article. Libraries and librarians also consider journal rankings in collection development decisions.
The established source for journal rankings is Journal Citation Reports (JCR).The NMSU Library does not have a subscription to JCR, but offers alternative sources for journal rankings within this guide. See the Sources for Journal Rankings page for more information.
Definition: The journal impact factor measures the importance of a journal by calculating the times its articles are cited.
How Impact Factor is Calculated: The ISI calculation is based on a two-year period and involves dividing the number of times articles were cited by the number of articles that are citable.
To note: Experts stress that there are limitations in using impact factors to evaluate a scholar's work. There are many reasons cited for not relying on impact factor alone to evaluate the output of a particular individual. Among these are the following:
According to Jim Testa, a researcher for Thomson Reuters (ISI), the most widespread misuse of the Impact Factor is to evaluate the work of an individual author (instead of a journal). "To say that because a researcher is publishing in a certain journal, he or she is more influential or deserves more credit is not necessarily true. There are many other variables to consider."
Because impact factors vary among disciplines, one cannot meaningfully compare two journals in different disciplines using impact factors. For this reason, it is helpful to see how a journal ranks based on other journals in the subject category. First find the journal to see what discipline or subject category/categories it falls within. Then find the total number of journals in the subject area. Subtract the ranking of the journal from the total number of journals and divide by the number of journals in the subject area minus 1. Thus you will find the percentile ranking.
n=number of journals in the subject category
n-rank/n-1 x 100 =percentile