The best colleges for your money may not be what you think they are

High school students and their parents might do well to spend a little more time perusing the materials of their in-state public universities, and less time pouring over the catalogues of coveted private schools - especially if they're trying to get the biggest bang for their buck.

According to a projected forecast from the research firm PayScale, public universities will provide a significantly higher financial return on investment than their private counterparts.

Already, "public colleges (as a group) out-perform private colleges for financial ROI by 13%," they write. In 2015, the 20-year net return on a bachelor's from a public school is about $490,000. For a private school, it's closer to $430,000.

And if tuition increases and wage growth continue at their current rates, that gap will only grow over the next decade.

By 2025, they predict the 20-year ROI gap between public colleges and private ones will reach 24%. (More about their methodology here.)

A decade ago, private colleges were "typically the better bet in terms of financial return on investment post-graduation," writes PayScale's Lydia Frank. But the landscape has changed, and "what we've seen is that a school's brand is much less impactful for alumni than it used to be," Frank tells Business Insider.

Going to college, she notes, is almost always worth it. But the potentially astronomical costs of doing so are a "huge factor in terms of a graduate's ultimate ROI" - and on average, the scale tips in favor of public institutions.

That doesn't mean private universities never pay off (and this study from the MacArthur Foundation provides a nice defense of liberal arts colleges), but Frank says it does suggest that private colleges probably aren't worth going into debt for - even for elite brand-name schools.