It really all comes down to effective studying, and is very accessible to all income levels. Just buy one or two good prep books, and get access to practice tests (I used only the ones in the books, BTW). I didn't enter into any SAT prep program, and always felt they were for people who did not know how to study well.
It doesn't even require much intensity if you do it right. For both the SAT and the GRE, I began studying 9-12 months before I expected to take the exam. I spent only a small amount of time a week on it (1-2 hours). The trick was to be regular and consistent. Towards the end, start taking practice tests. I got a pretty good score on the SAT and a fantastic score in the GRE (easily in the 99 percentile range).
No tutors. No prep programs. Just a bunch of books, and 1-2 hours a week. That's all it takes.
Again, I'm just saying that for many students, reading this article would expose them to something that they haven't really been exposed to so far.
So now we know the secret of poorly performing kids. Well, of course, if you want an ambitious score, you study. If you don't, you do not get a good score.
I think my other point was that it does not require a lot of study! I studied more for my usual classes in school than I did for the SAT/GRE. But if you try to cram it all in 3 months before the SAT, you're setting yourself up for trouble.
I did well in high school only studying on the train into school on the days of exams. That formula worked for me, and I figured everybody else did something similar. I knew I had to "study" for the SAT if I wanted to better than average, and practicing vocabulary during homeroom seemed like more than what everybody else was doing.
I happened to get into a good college and really struggled the first year. I studied harder than usual, but it wasn't until I started studying with some friends that I saw how much more work other people put into school.
once i got there, it wasn't easy. mainly because i didn't really care about school, and refused to put in the time. apparently cramming doesn't work for linear algebra unless you are a genius, which i'm not.
I would wager that most kids don't want to put in the work to be a true over-achiever. Or because they haven't been raised that way. Not because they're unaware of the benefits.
I'm trying not to fall into the trap of suggesting the reason for success is "hard work" when socioeconomic differences in opportunities explain much or all of the gap. But that truly seems to be the thesis presented here.
It's not that there is some bit of knowledge that poor kids don't have, it's that they have no one to mimic. There are a million little decisions that go into how to spend your time in high school. Figuring out the best way to spend it is far too big of a task for any one student. The only way to have any hope of spending it well is to copy what others have done and learn from their mistakes. In elite schools, you have much better role models to mimic. If you want to go to Harvard, you can mimic what that kid who got into Harvard did last year.
A general principle like "just work hard if you want to succeed" is worse that useless for a kids in mediocre school districts. Not only does it do nothing to show them how to actually spend their time, but it's so general that it can never be proved "wrong." So if a student tries to do what they consider "hard work" and that doesn't lead to success, people aren't going to stop saying it because it didn't work. Moreover, since the kid who failed knows that they were given "correct advice" they're just going to blame themselves for their failure rather than realizing that they have the same potential as people in better school districts, they just don't have as much opportunity to realize it.
Still, advice like "work hard to succeed" will always be "wrong" in the sense that it's the wrong thing to tell a young person. No matter what advice you give a young person, it needs to be much more specific and personalized if you want it to have a reasonably good chance of being understood and used correctly. You can't expect someone with so little life experience to fill in the blanks for themselves.