The National Academy of Engineering convened a three-day workshop from May 24-26, 2021, which sought to define directions for future research on best practices, metrics, and policies that promote diversity in engineering and how they fit into the larger system of recruiting and retaining engineering students from all backgrounds. Workshop discussions examined the system of higher education admissions, transfer and 3+2 programs, research on admissions, and the advantages of and concerns with using artificial intelligence and data science tools in recruiting, admissions, and retention. This publication summarizes the presentations and discussions of the workshop.