Randomized Controlled Trials Commissioned by the Institute of Education Sciences Since 2002: How Many Found Positive Versus Weak or No Effects

Education in 2002, IES has commissioned a sizable number of well-conducted randomized controlled trials (RCTs) evaluating the effectiveness of diverse educational programs, practices, and strategies (“interventions”). These interventions have included, for example, various educational curricula, teacher professional development programs, school choice programs, educational software, and data-driven school reform initiatives. Largely as a result of these IES studies, there now exists – for the first time in U.S. education – a sizable body of credible knowledge about what works and what doesn’t work to improve key educational outcomes of American students. A clear pattern of findings in these IES studies is that the large majority of interventions evaluated produced weak or no positive effects compared to usual school practices. This pattern is consistent with findings in other fields where RCTs are frequently carried out, such as medicine and business,1 and underscores the need to test many different interventions so as to build the number shown to work. Based on our careful count, what follows is the breakdown of positive versus weak or null findings in the IES studies: • A total of 90 interventions have been evaluated in IES-commissioned RCTs. Of these: − 11 interventions (12%) were found to produce positive effects