Testing the Testing: Validity of a State Growth Model

Possible threats to the validity of North Carolina’s accountability model used to predict academic growth were investigated in two ways: the state’s regression equations were replicated but updated to utilize current testing data and not that from years past as in the state’s current model; and the updated equations were expanded to include additional socioeconomic, financial, and demographic variables. The updated equations were found to explain a very low proportion of the variance in growth statewide, with R2 values ranging from .054 to .135. This suggests that the state’s model is extremely unpredictive of academic growth. The expanded equations were found to offer almost twice as much predictive power as the updated equations and, hence, the state’s model.