Are Gain Scores Really a “Treacherous Quicksand”? An Empirical Comparison Between Gain Score Methods and ANCOVA

Gain score methods have long been criticized and avoided in educational and psychological literature and research. Using a novel research design that allows researchers to know the true causal effect in the presence of real, not simulated, confounding, this article provides empirical evidence that gain score methods can outperform ANCOVA in a real educational setting. Prevalent uninformed criticism on gain score methods should be discredited.