The Doctoral Review Committee is the official advisory committee to the Associate Department Head for the Ph.D. Program and the Department Head. While the structure and contents of the Ph.D. program are still discussed by the faculty and students as a whole, the DRC makes sure that the program's design is implemented and rules abided by properly. In this sense the DRC is also an oversight committee.
The DRC monitors all courses. It regularly asks students to evaluate courses and their instructors. It keeps statistics and data about all past and present CS Ph.D. students, discusses issues and problems that are specific to CS Ph.D. students, and makes minor policy decisions that do not require the attention of all the faculty and students.
The DRC is also something like a senate since the student representatives speak for all the students and the faculty representatives speak for all the faculty.