Henry L. Roediger III reviews how tests make us smarter:
One insight that we and other researchers have uncovered is that tests serve students best when they’re integrated into the regular business of learning and the stakes are not make-or-break, as in standardized testing. That means, among other things, testing new learning within the context of regular classes and study routines.
Students in classes with a regimen of regular low- or no-stakes quizzing carry their learning forward through the term, like compounded interest, and they come to embrace the regimen, even if they are skeptical at first. A little studying suffices at exam time — no cramming required.
Moreover, retrieving knowledge from memory is more beneficial when practice sessions are spaced out so that some forgetting occurs before you try to retrieve again. The added effort required to recall the information makes learning stronger. It also helps when retrieval practice is mixed up — whether you’re practicing hitting different kinds of baseball pitches or solving different solid geometry problems in a random sequence, you are better able later to discriminate what kind of pitch or geometry problem you’re facing and find the correct solution.
Surprisingly, researchers have also found that the most common study strategies — like underlining, highlighting and rereading — create illusions of mastery but are largely wasted effort, because they do not involve practice in accessing or applying what the students know.
When my colleagues and I took our research out of the lab and into a Columbia, Ill., middle school class, we found that students earned an average grade of A- on material that had been presented in class once and subsequently quizzed three times, compared with a C+ on material that had been presented in the same way and reviewed three times but not quizzed. The benefit of quizzing remained in a follow-up test eight months later.