I am primarily a meta-analyst, and the majority of my work involves using, explaining, and seeking to improve techniques used in systematic reviewing and meta-analysis as a means of helping policymakers and practitioners solve problems that affect the quality of people’s lives. Although my main area of interest is educational policy, broadly defined, I have applied my expertise to a range of issues, including public health, social welfare, and development. I am an invited member of the Society for Research Synthesis Methodology; the co-editor, with Harris Cooper (Duke University) and Larry Hedges (Northwestern University), of the second and third editions of the Handbook of Research Synthesis and Meta-Analysis (Russell Sage Foundation); an associate editor of Research Synthesis Methods, a peer-reviewed journal; co-editor (with Julia Littell and Sarah Young) of an interactive, online textbook in systematic reviewing and meta-analysis hosted by the Open Learning Initiative; and from 2012-2025, served as one of the Principal Investigators for the U.S. Department of Education's What Works Clearinghouse.