It could still be correlative; 'lifestyle choices' are basically the definition of correlation not causation. Or were you being sarcastic? For another (probabl

It could still be correlative; 'lifestyle choices' are basically the definition of correlation not causation. Or were you being sarcastic? For another (probably unhelpful) anecdote, got great grades in my senior year of college when I had a scholarship. One semester in my junior year I took 18 credits and also worked 32 hours a week through a 45-minute-one-way commute...I got very little sleep and my grades suffered for it. The primary things I learned that year were (1) don't over-commit yourself, (2) make a schedule and stick to it if you need to get the bare minimum done and don't have time to do everything, (3) you don't actually have to attend every lecture or turn in/complete every assignment to pass a class, (4) long commutes suck, and (5) a little bit of VHDL syntax stuck around was about the only thing I learned in those classes. My bad grades were not caused by poor sleep, poor sleep was a side effect of a larger issue (namely, the perpetual problem of money).