(Reuters) - U.S. News & World Report is postponing plans to release a new ranking of law schools based on their racial and ethnic diversity, after deans raised concerns that the company wasn't counting multiracial students as underrepresented minorities.

Robert Morse, U.S. News & World Report's chief data strategist, told University of Oregon School of Law Dean Marcilynn Burke Thursday, in email obtained by Reuters, that the diversity-based ranking that was set to be published on March 30 will now be released at a later, "undetermined date."

"After receiving your feedback, we decided to remove the law diversity ranking so we can devote more time to ensuring it accurately reflects the data of underrepresented minorities, including students of two or more races," Morse said in the email.

He did not immediately respond to requests for comment.

The deans of more than 160 law schools, including Yale, Stanford and Berkeley, signed on to a Wednesday letter to Morse that said they had recently learned multiracial students would not be counted as underrepresented minorities, calling the approach "simply wrong and unacceptable."

"These students consider themselves, and are considered by others, to be racially diverse, and they are underrepresented in the legal profession," the deans wrote in the letter. "We urge that U.S. News co rrect [sic] this error immediately and before its rankings are published next week."

The deans said in their letter that U.S. News had already made another "essential change" they pushed for by including Asian students in calculating diversity.

U.S. News, which releases rankings of law schools each year based on factors like peer assessments, selectivity and job placements, is often a go-to for prospective law students figuring out where to apply.

The company had planned to publish its first standalone diversity rankings this year, based on what percentage of a law school's student body identifies as an underrepresented minority.

The diversity ranking would come as top law firms face pressure from clients to recruit and retain more diverse talent out of law school.

"If you're going to look at going outside of whatever you consider your top feeder schools, this could have been an important and useful tool," Oregon's Burke said in an interview Thursday. "But if they relied upon it as U.S. News had planned to roll it out, it would have been a very skewed tool."