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National Center for Education Evaluation and Regional Assistance


Random Assignment in Program Evaluation and Intervention Research: Questions and Answers

What is the purpose of education program evaluation?

The basic purpose of program evaluation research is to test (1) whether education programs help the students they are designed to serve and (2) whether new ideas for education programs still under development are worthy of extension to a wider selection of schools and settings. The term “program” refers to a specific set of education practices or interventions that are thought to have an impact on a given set of education outcomes.

For example, imagine that a new math program appears to show promise in improving students' math skills. But before teachers, school administrators, and education policymakers make that program a permanent part of the curriculum, they will want to know whether the program actually helps students learn mathematics better than the usual program. To answer this question, a local school district, a state Department of Education, or the U.S. Department of Education may commission a study to evaluate the new program. This effort would involve setting up the program in certain schools or classrooms to examine how students in the program are doing in math compared to other students not in the program. In technical terms, this examination is called an "impact study" because its purpose is to determine the impact, or the effect, of the program on students' math skills. The impact is defined as the difference between the math skills of students in the new program and the math skills of students not in the program. The most reliable and accurate way to conduct an impact study is through a technique known as random assignment.

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