This commentary discusses the three articles in this (2017) issue. The articles expand the published research base on the effectiveness of early education in the sub-Saharan Africa countries of Zambia, Kenya, and the Democratic Republic of Congo (DRC). Each of the three articles employs rigorous methods to better understand the impact of classroom-based programs, in either preprimary or primary schools, designed to improve participants' outcomes in reading, mathematics, and socio-emotional development. Articles such as these that describe the characteristics, scope, and limitations of research findings are valuable to the global educational community, especially to those who design and/or implement improved programs or practices. This commentary examines: What methods work, under what conditions, and why? Which methods best answer the questions of what works, under what conditions, and why? and What will it take to get more studies like these completed and into the hands of practitioners and policymakers? [This commentary discusses Jukes et al., 2017 (EJ1147933), McCoy et al., 2017 (EJ1147934), and Aber et al., 2017 (EJ1147937).]