It's smart to be skeptical of education studies that seem to support traditional practices.
It’s not unusual to read that a new study has failed to replicate—or has even reversed—the findings of an earlier study. The effect can be disconcerting, particularly when medical research announces that what was supposed to be good for us turns out to be dangerous, or vice versa.
Qualifications and reversals also show up in investigations of education and human behavior, but here an interesting pattern seems to emerge. At first a study seems to validate traditional practices, but then subsequent studies—those that follow subjects for longer periods of time or use more sophisticated outcome measures—call that result into question.