Pulled this from:

Eigenfactor.org

 

 

 

·  How do I interpret a journal's Eigenfactor® score?

A journal's Eigenfactor score is our measure of the journal's total importance to the scientific community.

With all else equal, a journal's Eigenfactor score doubles when it doubles in size. Thus a very large journal such as the Journal of Biological Chemistry, which publishes several thousand articles per year, will have extremely high Eigenfactor scores simply based upon its size.

Eigenfactor scores are scaled so that the Eigenfactor scores of all journals listed in Thomson's Journal Citation Reports (JCR) sum to 100. Thus if a journal has an Eigenfactor score of 1.0, it has 1% of the total influence of all indexed publications. In 2013, the journal Nature has the highest Eigenfactor score, with a value of 1.603.

·  What is the Normalized Eigenfactor® score and how does it relate to the Eigenfactor score?

The Normalized Eigenfactor score rescales the Eigenfactor score to make the scores easier to read an interpret. The Normalized Eigenfactor score is scaled so that the average journal has a score of 1. Journals can then be compared and influence measured by their score relative to 1; a journal with a Normalized Eigenfactor Score of 3 has three times the total influence of the average journal in the JCR.

Mathemetically, the Normalized Eigenfactor score is equal to EF*N/100, where EF is the corresponding Eigenfactor score and N is the number of journals in the JCR in the year in question. Because the Normalized Eigenfactor score is a simple multiplicative rescaling of the Eigenfactor score, the percentile rank of the jounal is the same for both metrics and the ratio of two journals' scores are also the same for the two metrics.

·  How do I interpret a journal's Article Influence® score?

A journal's Article Influence score is a measure of the average influence of each of its articles over the first five years after publication.

Article Influence score measures the average influence, per article, of the papers in a journal. As such, it is comparable to Thomson Scientific's widely-used Impact Factor. Article Influence scores are normalized so that the mean article in the entire Thomson Journal Citation Reports (JCR) database has an article influence of 1.00.

In 2006, the top journal by Article Influence score is Annual Reviews of Immunology, with an article influence of 27.5 . This means that the average article in that journal has twenty seven times the influence of the mean article in the JCR.

·  Do Eigenfactor® scores and Article Influence® scores take journal subscription prices into account?

We do not use journal subscription prices when computing the Eigenfactor and Article Influence scores. However, we do display journal price information on the journal details pages. Our subscription cost effectiveness search ranks subscription-based journals according to the value-per-dollar that they provide, and our open access cost effectiveness tool compares the article-processing fees charged by open access journals.

·  What are the Eigenfactor® field categories, and how do they compare to the Thomson-Reuters JCR field categories?

In short, the Eigenfactor categories derive from our efforts to map the structure of science.

The Eigenfactor categories differ from the Thomson-Reuters JCR categories in a number of ways. For one thing, the Eigenfactor categories form a hard partition in which each journal belongs to only one category, whereas the Thomson categories form a soft partition in which journals are allowed multiple category membership.

Second, our approach to mapping the structure of science is not to use our preconceived notions about what the structure of clusters or "fields" within science should be, but rather to let the data - in our case, citation patterns - tell us what the clusters or fields are. In other words, we are interested in mapping science according to what researchers do, not what they say that they do or how they self-identify. One interesting consequence of this approach is that the fields vary widely in size according to their citation behavior. Some fields, such as Tribology (the study of friction) are very small and comprise only a few journals; others fields are very large and contain multiple subdisciplines that might typically be considered separate. For example, the Molecular Biology cluster on our map includes genetics, developmental biology, microbiology, and biochemistry - areas that might be in different departments or even different colleges at many universities.

Because the Thomson-Reuters JCR categories may be preferable to the Eigenfactor categories for some purposes, we list both, and we allow userse to search journal rankings by Thomson-Reuters category as well as by Eigenfactor category.

The citation data used at Eigenfactor.org come from Thomson Scientific's Journal Citation Reports (JCR). The JCR provides detailed information about more than 8,000 journals in the sciences and social sciences which are indexed in the Thomson-Reuters Web of Science citation database. Information about subscription prices comes primarily from journalprices.com.

Hopefully this might be helpful.

 

 

Lynn Haggard

Virtual Services Librarian

Forsyth Library

Email:  refserv@fhsu.edu OR lhaggard@fhsu.edu

Phone:  785-628-5566

 

 

 

Can someone look up the impact factor for State Politics and Policy Quarterly and share it with me?

We do not have a subscription to Journal Citation Reports and I just need the info on that one title.

Thanks in advance!

Pat Dover

 

Patricia Dover

Electronic Resources Librarian

Collections Management

Jessie Ball duPont Library

The University of the South

178 Georgia Ave.

Sewanee, TN 37383

931.598.1657

prdover@sewanee.edu

 

 

 

 

 

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