...students who read a passage, then took a test asking them to recall what they had read, retained about 50 percent more of the information a week later than students who used two other methods.
The tests, it's important to note, were old fashioned essay tests. The investigators called it retrieval practice.
When I was a third year medical student one of our resident mentors understood this. He told us we would have no trouble passing the upcoming exam if for each clinical topic encountered we would write the material down in our own words and study as if preparing to give a mini-lecture on the topic.
Primary source from Science.
HT to Instapundit.