USC is the most overrated team and BYU is the most underrated team in AP poll history.
Since the AP poll began preseason rankings in 1950, USC has had 17 more preseason than final rankings. Notre Dame and Ohio State were tied for second with 14 each.
Conversely, BYU started in the AP poll 12 times but finished ranked 20 times, netting 8 more final than preseason rankings. Baylor and Boston College tied for second, with 7 each (8 vs 15 and 4 vs 11 respectively). Do AP voters have an odd subconscious bias against religious schools starting with "B"?
See the attached tables for a detailed look at the most over- and under-rated teams across 5 periods: the last 75, 50, 25, 10, and 5 years.
I've included teams in the top or bottom 5 for any period or top/bottom 10 for two periods. For context, Michigan, Alabama, Clemson, LSU, and Miami are also included despite not meeting these criteria.
Analysis shows USC, Texas A&M, Oklahoma, North Carolina, and Wisconsin as significantly overrated. However, Ohio State, Notre Dame, Texas, Washington, and UCLA have recently met expectations.
BYU is notably under-hyped, leading as the most underrated team in 4 of the 5 periods considered.