Background: Over the years, the quantity and quality of educational research has been rapidly improving. This can be attributed to the growing call to use evidence of effectiveness in decision-making by policymakers and practitioners. In fact, evidence sufficient to establish programs as "small", "moderate", or…

The public narrative surrounding efforts to improve low-performing K-12 schools in the United States has been notably gloomy. But what is known empirically about whether school improvement works, which policies are most effective, which contexts respond best to intervention, and how long it takes? We meta-analyze 141 estimates from 67 studies of…