The law journal rankings were updated in mid_November for 1999-2006 at http://lawlib.wlu.edu/LJ/index.aspx The most significant change is a new ranking that combines the impact-factor and total-cites scores into a combined ranking. The new ranking is normalized so that the top ranked journal(s) in a retrieved set will always have a value of 100 and other journals will have a lesser score in proportion to each journal's combined-score. Although combined-score is intended to be the primary ranking (and is the default ranking for author submission purposes on the website) the separate rankings by total-cites and by impact-factor are still available.
Combined-score ranking is based on the idea proposed by Ronen Perry that neither ranking by total cites nor by impact-factor are in themselves sufficient, and need to be combined. See, "The Relative Value of American Law Reviews: Refinement and Implementation" available at SSRN: http://ssrn.com/abstract=897063 (to be published in the Connecticut Law Review) . The problem in any combined ranking is what weight to give to the underlying factors. Perry calculated a weight of 0.577 for impact-factor (and thus 0.433 for total cites) based on the idea that Harvard Law Review and Yale Law Journal have equal prestige, and 0.577 is the weight that makes the combined impact-factor and total-cites counts equal for these journals (over the survey period of 1998-2005). However, the default weighting used on the website is a slightly different value of 0.57. It was decided to use 0.57 because that weighting gives Harvard Law Review a normalized rank of 100 over each of nine rankings (1991-1998...1999-2006) while maximizing the average of Yale Law Journal's rank during those same years. While Harvard Law Review and Yale Law Journal are generally considered comparable, Harvard is still widely regarded as the gold-standard and deserves an edge over this period. It is expected that the 0.57 weighting will continue to be used in future annual surveys, and thus Harvard Law Review may at some time drop below a combined-score ranking of 100.
A webpage is available that shows for each law journal how many total cites to an article would have to occur over the following 8 years in order to make such an article worth publishing (from a combined-score ranking point of view). For the Yale Law Journal, for example, the number is '9', so in other words, if it's "known" that an article/note/review/introduction/obit... will receive less than a total of 9 cites during the 8 years after it's published then publishing the item will reduce Yale Law Journal's combined-score (see, http://lawlib.wlu.edu/LJ/citesneeded.aspx). Note, however, that because ranking is based on rounding to one decimal place, small changes in combined-score may not change a journal's actual ranking.
Note also that the immediacy index has been removed from the website. An immediacy index is a method for comparing how rapidly the average article in a particular journal will be discovered and cited. For example, the 2004 immediacy index figures were based on the number of articles citing each journal's articles dated 2004, where the citing articles are dated 2003 or 2004. It was felt that this index was not sufficiently used to justify maintaining it.