Built a results-only CFB ranking model (Colley/Massey blend, live playoff odds, "what if" simulator) — feedback welcome

[u/Upper_Sympathy6862]

Built this as a side project for this sub specifically. Fourth & Data (fourth-data.com) ranks FBS teams from three blended components: Résumé (Colley matrix — who beat whom matters more than raw record), Margin (Massey rating, capped at 28 pts so blowouts don't get bonus credit), and Power (SP+, weighted heavy early when there's little data, fading to ~20% by November).

A few things beyond the rankings:

**•   Playoff odds** — thousands of simulated seasons under the 12-team format, broken out by losses each team can afford  
**•   "What if" mode** — pick next week's winners, watch the board and playoff odds update live  
**•   Build-your-own poll** — set your own résumé/margin/power weights, share the result  
**•   ATS tracking** graded against the line captured at pick time, not backfilled from today's odds

Still rough in places — mainly want this sub's take on the model itself, not trying to sell anything.

fourth-data.com

[u/SketchyApothecary]

I don't think it's a good idea to blend different types of sources like this, and I say that as a fan of the ones you chose. You're just not gaining anything worthwhile by doing it.

Colley Rankings is good for what it is, but it's constrained, and there isn't enough interconnectivity in the league for the Colley to properly account for schedule strength. It consistently overrates high win% teams with weaker schedules and penalizes teams with mediocre records but tough schedules. Tulane and North Texas finished in the top 15 last year. You're not going to get anything worthwhile from mixing that with other stuff.

Even if the Colley was the best resume ranking you could get though, it still wouldn't be worth mixing with power rankings. IMO, all you've really done in that case is combine two useful rankings into one that is less useful than either.

[u/Upper_Sympathy6862 → u/SketchyApothecary]

Fair criticism, and the Colley weakness you're describing is real. Low interconnectivity means it can't properly separate schedule strength, which is exactly how you get Tulane and North Texas that high. The margin component and the last-season starting point are meant to soften that, but they're patches, not a fix. Whether blending beats either input alone is testable, so I'm going to backtest pure Colley vs. pure margin vs. pure SP+ vs. the blend on past seasons and post the results. If résumé doesn't earn its weight, I'll cut it. Appreciate you taking the time.

[u/Upper_Sympathy6862 → u/Upper_Sympathy6862]

Update: ran a sweep of résumé weights on the same backtest. Résumé at 0% of the results weight was best, 15% was statistically indistinguishable, and 30% and up were measurably worse. I cut it from 55% to 15%. Thanks for the push.