One of the central tenets of raising kids in America is that parents should be actively involved in their children’s education: meeting with teachers, volunteering at school, helping with homework, and doing a hundred other things that few working parents have time for. These obligations are so baked into American values that few parents stop to ask whether they’re worth the effort.

Until this January, few researchers did, either. In the largest-ever study of how parental involvement affects academic achievement, Keith Robinson, a sociology professor at the University of Texas at Austin, and Angel L. Harris, a sociology professor at Duke, mostly found that it doesn’t. The researchers combed through nearly three decades’ worth of longitudinal surveys of American parents and tracked 63 different measures of parental participation in kids’ academic lives, from helping them with homework, to talking with them about college plans, to volunteering at their schools. In an attempt to show whether the kids of more-involved parents improved over time, the researchers indexed these measures to children’s academic performance, including test scores in reading and math.

What they found surprised them. Most measurable forms of parental involvement seem to yield few academic dividends for kids, or even to backfire—regardless of a parent’s race, class, or level of education.

Do you review your daughter’s homework every night? Robinson and Harris’s data, published in The Broken Compass: Parental Involvement With Children’s Education, show that this won’t help her score higher on standardized tests. Once kids enter middle school, parental help with homework can actually bring test scores down, an effect Robinson says could be caused by the fact that many parents may have forgotten, or never truly understood, the material their children learn in school.