"Students who self-test frequently while studying on their own may be able to learn more, in much less time, than they might by simply studying the material over and over again," he adds. "Incorporating more frequent classroom testing into a course may improve students' learning and promote retention of material long after a course has ended."

Perhaps equally important, this study demonstrates that students who rely on repeated study alone often come away with a false sense of confidence about their mastery of the material.

Doesn't seem so surprising. Active recall is supposed to work better than passive recall for enshrining memory. It's why flashcards work better than lists. There's theory for this all over and if you google, you'll find tools to help you learn using graduated interval recall as well. These work on the theory that each time you recall something, you keep it for a little longer before needing a reminder. They vary in sophistication, but the concept seems useful to me, and fits my experiences as well, which never hurts.

Repeated test-taking better for retention than repeated studying, research shows