The United States is at a critical juncture in its ability to remain internationally competitive in Science, Technology, Engineering, and Mathematics (STEM). At present, too few people from diverse populations, including women and minorities, participate in the STEM academic and workforce communities. This issue brief is the first in a series produced by AIR to promote research, policy, and practice related to broadening the participation of traditionally underrepresented groups in STEM doctoral education and the workforce. The material is based upon work supported by the National Science Foundation.