This is just a small data point to back up a claim I've made a few times that today's youth are better adjusted than at least the past generation. I think looking at this data makes an important point, I hear too many claims about our country's ills being due to something like moral decay or individuals today being less responsible than in the past. I am not aware of any data to back up the claims that our problems are individual level instead of at the level of state and national institutions. This is just another small series of data points to back up my assertion that the youth today are pretty good and pretty responsible, so irresponsibility does not seem to be a likely cause of our nation's ills.
Of course, this data doesn't go directly to my point, it simply shows that use of illicit substances is down and that teens are less likely to have sex. But it's not a big jump to believe that these behaviors might be correlated with other socially beneficial behaviors (like working hard and trying to get into a good school). If I was feeling ambitious I could probably get data on college entry and hours worked, but I'm not feeling that ambitious today. Still, I think it's important to note that there is data supporting the idea that today's youth are more responsible than the last generation, and that it's plausible to believe they are harder working as well (what I remember from hours worked and proportion working seems to back this up as well, but I'd have to recheck the numbers since it has been awhile). If we want to solve our problems it's important to accurately diagnose what they aren't and data like this helps us do this.