According to MedPage, a new study has found that college students who consider themselves “morning people” are more likely to have better grades than those who are “evening people.” In fact, the benefit of being a morning person was a “full letter-grade difference.”
Researchers surveyed 824 undergraduate students about their sleep habits and daytime schedules. Even after they accounted for academic ability, social ability and SAT verbal scores, researchers found that students who were morning-types were more likely to have better grades than those who considered themselves evening-types.
My Take? 

You should know that this study was published as an abstract and presented as a poster at a conference. And, you should know that many papers presented like this are too weak to ever see the light of a peer-reviewed medical journal. Therefore, these data and conclusions should be viewed with suspicion until published.
Nevertheless, we know that kids who get enough sleep (i.e., 8-9 hours per night) tend to be more highly healthy. They are less obese. And, they perform better in school. I bet you a nickel that if the researchers looked that they would find the “morning people,” with better grades, had more and better sleep.
To help you child or teen sleep better, consider reading about the topic in my book God’s Design for the Highly Healthy Child or God’s Design for the Highly Healthy Teen.