From Rutgers "University Regulations & Procedures Manual"

60.5.17  PROMOTION TO PROFESSOR, DISTINGUISHED PROFESSOR, OR EQUIVALENT RANKS

C.  The designation of Distinguished Professor is reserved for those faculty in the University (usually already in the rank of professor) who have achieved scholarly eminence in their discipline and fields of inquiry. The standard for promotion to Distinguished Professor is significantly higher than that applied in promotion to Professor. The most significant area of consideration in determining promotion to Distinguished Professor for general teaching/research faculty is scholarship.... Only those faculty who have demonstrated outstanding achievement in [that area] by earning significant recognition inside and outside the University are eligible for promotion to Distinguished Professor. Typically, such recognition is reflected in national and international reputation in one's discipline. Teaching and service also apply to the general evaluation of a candidate for promotion to Distinguished Professor. A candidate for promotion to Distinguished Professor should be an exemplary member of the University faculty who consistently has demonstrated a high standard of achievement in all professorial roles.