This article was part of a special supplement in the Food and Nutrition Bulletin on the Alive & Thrive (A&T) project. Traditionally, impact evaluations have focused primarily on answering what impact programs or interventions have, with less attention to how or why impacts are achieved, or not achieved.The Alive & Thrive initiative, a 6-year program that aims to improve infant and young child feeding (IYCF) practices and reduce stunting in Bangladesh, Ethiopia, and Vietnam, has a specific objective to generate learning on how to achieve and replicate Alive & Thrive’s impact.