Now there is scientific data to back it up. A new article in the Journal Science, as reported in the New York Times, claims that people who take a test about what they have just read retain up to 50 percent more of that information a week later than people who just study notes.
So instead of just trying to memorize what you have written down, maybe it would be better to create a test for yourself. If there are questions at the end of a chapter in your textbook, you would be better off answering those questions than making flash cards for an hour so you could passively stare at them.