Some form of a short interrupted time series (ITS) is often used to evaluate state and national programs. An ITS design with a single treatment group assumes that the pretest functional form can be validly estimated and extrapolated into the postintervention period where it provides a valid counterfactual. This assumption is problematic. Ambiguous…

For more than four decades the National Assessment of Educational Progress (NAEP) has tracked the achievement of U.S. students in major academic subjects. This national resource is the only assessment that states and now many urban districts can look to as an objective yardstick of their performance over time, relative to national benchmarks, and…