This scholarly commentary addresses the basic questions that underlie program evaluation policy and practice in education, as well as the conditions that must be met for the evaluation evidence to be used. The evaluation questions concern evidence on the nature and severity of problems, the programs deployed to address the issues, the programs’ relative effects and cost-effectiveness, and the accumulation of evidence. The basic conditions for the use of evidence include potential users’ awareness of the evidence, their understanding of it, as well as their capacity and incentives for its use. Examples are drawn from studies conducted in the United States and other countries, focusing on evaluation methods that address the questions above.