At 3:53 PM ET on Sunday, U.S. News emailed Deans and other law school administrators the following:
Best Law Schools
For the overall ranking, U.S. News removed the metric for ratio of credit-bearing hours of instruction provided by law librarians to full-time equivalent law students [.25%, reducing the library weighting to 1.75%] and increased the weighting for the bar passage rate indicator [by .25%, for a new total of 2.25%]. As a result, we recalculated the rankings.
This change affected the overall ranking of 35 law schools, including 9 law schools in the Top 30.
Update: Karen Sloan (Law.com), US News' Rough Year Just Got Worse: Law School Rankings Changed a Third Time:
U.S. News & World Report has modified its closely watched law school rankings yet again—marking the third time the rankings have changed in the two weeks prior to their official March 30 release. ...
In a March 28 message to law school administrators, U.S. News said it removed a controversial metric regarding the number of credit hours taught by law librarians, and shifted the 0.25% weight that metric was given over to the bar pass rate indicator. As a result, the total weight given to law library measures in the overall rankings dropped from 2% to 1.75%, while the weight given to the bar pass rate increased from 2% to 2.25%, the message said. U.S. News recalculated the overall rankings with the new weighting, which changed the overall ranking of 35 schools, according to Pepperdine University Law Dean Paul Caron, who wrote about the latest changed on his TaxProfBlog. Nine of the schools in top 30 saw their rankings change, according to Caron, though several law faculty confirmed that there were no changes among the top 20 schools.
U.S. News did not explain the reason for ditching the law librarian teaching metric just two days before the official release of the rankings.