I don't doubt that the findings are the case, I've experienced it myself and seen it in plenty others. What I would've liked to see in the paper, though, is more proof of the cause-and-effect relationship's weight here: do people who naturally stay up late get worse grades, or do people who get worse grades end up with worse sleep habits?
I'd guess there's some degree of both, but without the study being more longitudinal (eg, tracking the same population across their entire time in college to see how their grades and sleep habits relate) it's hard to say. Purely anecdotally, I've seen people who start struggling (for reasons that have nothing to do with sleep) drift into a depressive/withdrawn existence that includes insomnia and sleeping late.
There are tons of lab experiments showing people's ability to learn goes down when they're sleep deprived. Memory consolidation seems to be one of the principle reasons sleep and given all the in-lab double blind studies it would be amazing if people getting less sleep didn't do worse in school. Which isn't to say that this particular paper or article proves that.
> There are tons of lab experiments showing people's ability to learn goes down when they're sleep deprived.
I get that, but instead of immediately jumping to sleeping later maybe we should look at why kids appear to be going to bed later. All of the devices and distractions have likely pushed people to stay up later and later. Maybe the fix is not to move school times, but have parents take devices away at a reasonable time.
Generally speaking young children will tend to go to bed earlier and wake up earlier than their parents and adolescents will go to bed later and wake up later. It's true that electric lights and computer screens have exacerbated the problem of teenagers wanting to sleep in but they didn't cause them in the first place.
I'd guess there's some degree of both, but without the study being more longitudinal (eg, tracking the same population across their entire time in college to see how their grades and sleep habits relate) it's hard to say. Purely anecdotally, I've seen people who start struggling (for reasons that have nothing to do with sleep) drift into a depressive/withdrawn existence that includes insomnia and sleeping late.