In the United States, the Juris Doctor is the degree that prepares the recipient to enter the law profession (as do the M.D. or D.O. in the medical profession and the D.D.S or D.D.M. in the dental profession). While the J.D. is the sole degree necessary to become a professor of law or to obtain a license to practice law, it (like the M.D., D.O, D.D.S, or D.M.D.) is not a "research degree". Research degrees in the study of law include the Master of Laws (LL.M.), which ordinarily requires the J.D. as a prerequisite, and the Doctor of Juridical Science (S.J.D./J.S.D.), which ordinarily requires the LL.M. as a prerequisite. However, the American Bar Association has issued a Council Statement, advising law schools that the J.D. should be considered equivalent to the Ph.D. for educational employment purposes. Accordingly, while most law professors are required to conduct original writing and research in order to be awarded tenure, the majority have a J.D. as their highest degree. Research in 2015 showed an increasing trend toward hiring professors with both J.D. and Ph.D. degrees, particularly at more highly ranked schools. Professor Kenneth K. Mwenda criticized the Council's statement, pointing out that it compares the J.D. only to the taught component of the US Ph.D., ignoring the research and dissertation components.