The Survey of Earned Doctorates (SED) has historically been used to report the number of new doctorates entering over 100 different academic disciplines annually, including the field of mathematics education. In this article, we examine the validity of the use of this measure for this purpose by analyzing data from 23 institutions that grant mathematics education doctoral degrees and a specific university. Results showed that the SED underestimated the number of doctoral graduates by 5-15%, raising concerns about the use of the SED for this purpose.