Parental aspiration for their children’s academic performance, the hopes or expectations that their kids will receive certain grades, can be a double edged sword. On the one hand, in moderation and with realistic goals, parental aspirations can help students achieve higher grades. But, according to a new study published in the Journal of Personality and Social Psychology, parents aiming too high can actually hurt their children’s grades.

The study looked at data collected from 3,530 secondary school students in Bavaria, Germany between 2002 and 2007, and backed it up with data gathered from a two-year study of over 12,000 high school students in the United States. The data was based on self-reported forms that tracked the student’s grades, their parents’ expectations, and how those changed over time.

And what they found was that “unrealistic” expectations often resulted in students doing worse in their classes. Pressure to achieve in high school is already pretty significant without parents laying on more at home. When parents aspire for their children to improve their grades, by small amounts at a time, they can actually help their children improve, because there’s a realistic, attainable goal that students can set for themselves.

When those expectations are too high though, like turning a D average into an A average in one semester, for example, it’s simply asking too much. School is hard, children have a lot on their minds, and they need to work on improving their grades step-by-step. If their parents expect too much, it seems like an insurmountable task, which puts even more pressure on the students, and leaves them spending more time worrying that studying, or leaves them exhausted and incapable of performing in school.

The study as focused on math, but the advice applies regardless: work with your children (or students!) to help them achieve better grades. Don’t set you sights too high, and remember that it’s a marathon, not a sprint.