Surprisingly, serious studies of homework can almost never prove that it has any benefit at all.

And the result of this fine-tuned investigation?  There was no relationship whatsoever between time spent on homework and course grade, and “no substantive difference in grades between students who complete homework and those who do not.”

This result clearly caught the researchers off-guard.  Frankly, it surprised me, too.  When you measure “achievement” in terms of grades, you expect to see a positive result — not because homework is academically beneficial but because the same teacher who gives the assignments evaluates the students who complete them, and the final grade is often based at least partly on whether, and to what extent, students did the homework.  Even if homework were a complete waste of time, how could it not be positively related to course grades?

And yet it wasn’t.  Again.  Even in high school.  Even in math.  The study zeroed in on specific course grades, which represents a methodological improvement, and the moral may be: The better the research, the less likely one is to find any benefits from homework.  (That’s not a surprising proposition for a careful reader of reports in this field.  We got a hint of that from Timothy Keith’s reanalysis and also from the fact that longer homework studies tend to find less of an effect.[5])

This is hard to swallow. Obviously, from our adult life experience, most of us know there is such a thing as learning by doing. To really master a concept or come up with a new idea, you have to struggle with it on your own over a period of time. Homework seems like it could prepare children to do that as adults, so if it is not, either the kind of homework given is the wrong kind, or it’s given at the wrong age where kids are not yet ready to benefit from it.