So ESPN did a pretty cool statistical analysis and breakdown of the "Best NFL Factories."
They used a fairly objective methodology for a number of different categories - % Overperformers vs. % Underperformers, Best QB Factory, Best Sleepers, Most Longevity, All-Pros and Pro-Bowlers, and Hottest School Now (Spoiler: it's us).
I like how they didn't try to combine all of these metrics into one formula and make a general, overall assessment. Instead, you can kinda see what each school has produced and why the stats infer what they do.
Ohio State has suffered somewhat from its large sample size, but that hasn't hurt Miami, LSU or USC too much.