In this brief, researchers describe limitations of both the interventions studied in the Employment Strategies for Low-Income Adults Evidence Review (ESER) and of the studies themselves. The brief highlights the more limited availability of research about the effects of employment and training programs on targeted populations such as hard-to-serve groups (those who are homeless, mentally or chronically ill, substance-dependent, or reentering the community from prison) and low-income males. It also identifies a lack of high quality research about interventions in rural settings, and about the effectiveness of some commonly implemented employment strategies. In addition, the brief identifies some of the challenges of interpreting results from the research review. The brief ends by recommending a research agenda to address these gaps and help build a stronger evidence base that could guide further improvements in program design and service delivery for low-income adults.