State assessments provide a relatively inexpensive and increasingly accessible source of data on student achievement. In the past, rigorous evaluations of educational interventions typically administered standardized tests selected by the researchers ("study-administered tests") to measure student achievement outcomes. Increasingly, researchers are turning to the lower cost option of using state assessments for measures of student achievement.
This NCEE Reference Report, Estimating the Impacts of Educational Interventions Using State Tests or Study-Administered Tests, identifies and describes the factors that could affect the precision of impact estimates when evaluations use state assessments instead of study-administered tests. The study is based on data from three randomized controlled trials.
The authors found that the impact estimates based on state assessments were not significantly different from the impact estimates based on study-administered standardized tests. However, they found significant differences in the precision of the impact estimates from models that used different combinations of the two types of tests to provide pre-test scores (scores from a test administered before the implementation of the intervention) and post-test scores (scores from a test administered after the implementation of the intervention). In particular, the authors found that: