Yeah, I suppose in reality 6 and 22 are not functionally different, but I had a notion that Tech and Purdue were comparable academically. And maybe also in football.
A lot of differences... (Note: some of these stats may not be perfectly apples-to-apples.)
Despite similar total enrollment, Purdue has about 2x the undergraduate enrollment, while Tech has about 2.5x the graduate student enrollment.
Despite being an "engineering school", only 1/3 of Purdue students are studying engineering. Apparently about 48% of GT undergrads graduate with an engineering degree.
But most importantly, these rankings are HEAVILY skewed to undergraduate graduation rates. This tends to really favor ultra-selective schools who only admit the can't-miss prospects. It tends to hurt schools with more egalitarian selection criteria who might take a chance on prospects who might flame out.
Purdue in particular is MUCH more selective for engineering, and for science. If you
look at the acceptance rates, the median SAT / ACT scores of those admitted, etc, it's high. But those two colleges is combined <50% of the student body. Other majors are far less selective.
But even then, Georgia Tech in 2026 had an overall acceptance rate
in 2026 had an overall acceptance rate of ~28% for GA residents and 9% OOS. That puts it below,
across all majors, Purdue's 34.1% admit rate for engineering.
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So tl;dr -- if you want to be an elite school, don't let anyone in who might even have a CHANCE of not making it out. If you do that, you climb the rankings, making even more students WANT to apply to your school, making it easy to ensure you never have to admit anyone who is a non-graduation risk. It's a virtuous or vicious cycle, depending on how cynical your perspective might be.