Heading off to college with a parent’s blank check in hand won’t help students earn high marks, according to sociologist Laura Hamilton. Hamilton’s study, published in the latest Annual Review of Sociology, finds that, regardless of the type of four-year institution they attend, students who receive greater financial contributions from their parents tend to earn a lower GPA along the way (even if they are more likely to complete their degree).

Hamilton says the effect on grades is “modest”—“not enough to make your child flunk”—but nonetheless “surprising because everybody has always assumed that the more you give, the better your child does.”

As the New York Times reports:

Dr. Hamilton found that the students with the lowest grades were those whose parents paid for them without discussing the students’ responsibility for their education. Parents could minimize the negative effects, she said, by setting clear expectations about grades and progress toward graduation.

“Ultimately, it’s not bad to fund your children,” [Hamilton] said. “My kids are little, but I plan to pay for them—after we talk about how much it costs, and what grades I expect them to achieve.”