Students enrolled in the Statistics Ph.D. program can petition for the award of this degree upon successful completion of eight term graduate courses in Statistics with an average grade of HP or higher, and two terms of residence. Approval from the Statistics Director of Graduate Studies is required.
Students enrolled in other Ph.D. programs at Yale can sometimes be eligible for the award of an MA in Statistics. The governing University regulation appears on page 512 of the 2012-13 edition of the Graduate School’s Programs and Policies:
Students enrolled in a Ph.D. program may receive a master’s degree from another department provided that it is in a related field of study and deemed necessary for the completion of the proposed dissertation research. The student’s proposed program of study must receive formal approval in writing from the director of graduate studies in both departments and the appropriate associate dean prior to enrollment in courses that will fulfill master’s degree requirements in another department. Courses taken toward a master’s degree in another department must be part of the student’s course requirement for the Ph.D., as approved by the director of graduate studies in both departments. However, such course work cannot also be counted toward a master’s degree in the department to which the student was admitted. A student may not advance to candidacy until all requirements have been completed for both the en route master’s degree in the program to which the student was admitted and the proposed master’s degree in a related field. Students who wish to obtain a master’s degree in a field that is not directly related to the doctoral degree must apply for a personal leave from the Ph.D. program and submit an application for admission to the master’s program. Any financial aid offered to the student for a Ph.D. program may not be transferred to a master’s degree course of study. Students enrolled in combined programs normally receive combined en route degrees as well.
The highlighted sentence explains why, currently, graduate students at Yale are only rarely able to follow this path to the MA in Statistics.