Legal Periodicals

Currency-Factor

A couple of years back I experimented with an immediacy index on the http://lawlib.wlu.edu/LJ page but decided to abandon it as the effort to create it didn't seem worth what I thought would be minimal usage. Since the methodology change in January 2008 now requires annual citation data to find the median impact-factor, the existence of such data is usable to automatically create an immediacy index. I still think it will be little used, but as it takes no effort to create it I've added it to the page, but renamed it "currency-factor".

Currency-factor aims to compare journals on how rapidly their articles become cited. It examines a three-year interval looking at how much the items published by a journal and dated during that same period are cited by articles made available during those same three years.
Taking the example of the 2000-2007 survey period; currency-factor is the number of articles added to Westlaw's JLR database in the three-year period of 2000-2002 that cite to volumes of a journal dated during those same three years, divided by the number of items published by the journal during those same years. It would have been desirable to create this index from the final three years of the survey period, but the data on which it's based, being automatically created from annual data collected to calculate impact-factor, is in a form requiring the use of the first three years of each survey period.

Law Journal Rankings 2000-2007

The law journal ranking page has been updated for the survey period
2000-2007, see http://lawlib.wlu.edu/LJ

Significant changes to the methodology occurred this year:

Instead of using Westlaw searches like VOL +1 JNL +6 YEAR searches were
changed to VOL +1 JNL /8 YEAR.

The final cut-off date for searches changed from October 31 to December
31

The Impact-factor calculation changed from a simple method of dividing
total cites over 8 years by items published in those 8 years, to a more
complex method of reporting the median value of the annual
impact-factors. The annual impact-factors being calculated by dividing
the cites received by a journal in each individual year of the survey
period by the items published by the journal in that same year and all
other years back to the beginning of the survey period.

The weight given to impact-factor vs. total cites in the combined score
ranking was reduced from 0.57 to 0.34

More information on these decisions is at
http://lawlib.wlu.edu/LJ/methodchange2007.asp