In this brief, we aim to support CCDF lead agencies and researchers by summarizing methods used in previous research and evaluation projects. We review 19 recent studies that examine efforts to improve the skills and professional development of home-based child care providers. Summary tables allow you to identify and review studies most relevant to your research. Reviewing others' approaches to research and evaluation can help you think about how to address your own research questions within available resources. For example, reading about target populations in past studies could lead your research team to discuss how to focus your sample to best answer questions of interest. Throughout the guide, we build upon the literature scan by sharing best-practice evaluation tips from a conversation with four experienced researchers. We hope this short summary of past research approaches and tips from research experts will help you design rigorous research that will inform state agencies and the field at large about how professional development and training interventions are being implemented and their effectiveness in improving caregiver skills, quality of care, and children's outcomes. (author abstract)