Small things the 2023–25 replays turned up. Some are built into the model or the blend, some are being watched, some we chose not to act on, and a couple are myths we can now put down. Each one carries a live tally for 2026, so the season tests it out of sample. Sample sizes matter: a 60-game finding has a standard error of about 6 points. The methods behind these are on the How it works page.
What we found. Over 24 seasons of outdoor games with weather on record: in wind of 15+ mph favorites won 62% against a 65% forecast (626 games); at 50F or colder they won 69% against 66% (1,517); above 75F, 61% against 63% (742). Scoring drops about 1.5 points below the total in wind.
What we did. The System shrinks toward 50 by a fifth in 15+ mph wind, adds 2 to the favorite in the cold, and shrinks by a tenth in heat, outdoors only. About +9 points a season, positive in every era. Forecasts come from Open-Meteo at kickoff.
What would confirm it. Favorites in windy games winning a few points less than the market says, again.
What we found. Nobody has tested this in a public game. FiveThirtyEight showed the raw crowd average, which trailed Elo. Here each player's pick is weighted by their season points (1 + points/50), and the result is scored like any forecaster.
What we did. "The sharp crowd" is a row on every leaderboard and the Predictions scoreboard next to the raw crowd, the market and The System.
What would confirm it. The sharp crowd finishing above the raw crowd over a season would show skill is identifiable; above the market would be news.
What we found. In our 2023-25 replays the favorite won 74% against a 66% forecast in these spots. Over 24 seasons (1999-2022, 2,312 games) the surplus is real but small: 69.2% against 67.7%, consistent across eras. An 8-point bump fitted to 2023-25 cost 40 points a season over the long run.
What we did. The blend pushes 2 points toward the favorite in these games (favorite at least 55%). Cards show a "Tight agreement" marker.
What would confirm it. Favorites winning a point or two more often than the average forecast in these spots; anything much larger would be a surprise.
What we found. Over 24 seasons, 943 games with a 10+ point gap: Elo's side won 50% while Elo claimed 63% and the market 49%. Our 2023-25 replays matched (49% vs 64%).
What we did. The blend averages the two, so it never follows Elo far from the market. The bold call of the week is shown as the contrarian view it is.
What would confirm it. Elo's side winning about as often as the market says, not as often as Elo says.
What we found. Week 18 Brier score: Elo 0.246, market 0.203, far wider than any other slice. Three of the 15 worst misses were week 18 games with clinched teams resting starters.
What we did. The simulation finds teams locked into a seed or eliminated; their games from week 15 on are forecast 25% Elo / 75% market, and other week 18 games 50/50. Ratings still update on pure Elo.
What would confirm it. The blended week 18 forecast scoring at least as well as the market that week.
What we found. Rookies started at a value of zero against a team value built by the previous starter, so Daniels was -25 in his second game, Dart -40, Ward -32. Three of the 15 worst misses. Fitted on 2021-25 rookie starters: first pick ≈ 40, late picks low 20s, undrafted 15, league mean start 49.
What we did. Rookies start at a draft-slot prior from nflverse draft data. The replay gained about 110 points from this and the warm-up fix together.
What would confirm it. Teams starting a rookie winning about as often as forecast, not less.
What we found. Replaying with half reversion instead of a third gained 37 points over three seasons (55 before the QB fix). Teams Elo lagged the market on most were regime changes: CIN, WSH, NE, NO, ATL, DET.
What we did. Offseason reversion is one-half.
What would confirm it. Elo close to the market in weeks 1-4, where it was worst (Brier 0.230 vs 0.223).
What we found. One pick a week over 24 seasons: strongest agreement went 379-71 (84.2%) against an 80% forecast, steady across eras (83%, 87%, 82%). Biggest disagreement went 217-233 (48%) while Elo claimed 62%. Our 2023-25 replays ran hotter (59-6) but the long run is the number to expect.
What we did. The lock of the week uses the agreement rule with a 2-point nudge. The bold call keeps the disagreement rule as the contrarian card.
What would confirm it. Locks hitting around 84% over a season; 80% would still be fine.
What we found. Home teams off a bye won 51% while Elo (+25 for the bye) said 61% (80 games). Away teams off a bye beat Elo by about the same (97 games). Tuning shows only 4 points between the bonus at 25 and at 0.
What we did. Left at +25. The two halves cancel and the samples are too small to act on.
What would confirm it. Teams off a bye winning less often than Elo says for a second season.
What we found. Monday night: home teams won 49% against a 58% Elo forecast; both models had their worst Brier score of any slot (63 games). Thursday night leaned the other way: 64% against 59% (59 games).
What we did. Nothing yet. Sixty games is a lead, not a rule.
What would confirm it. The same direction over 2026 Monday and Thursday games.
What we found. Thursday night: home teams won 64% against a 59% forecast (59 games).
What we did. Nothing yet.
What would confirm it. Home teams beating the forecast on Thursdays again.
What we found. Tuning preferred a home-field advantage of 35 Elo (about 1.4 points of spread) over 48, worth 13 points across three seasons, inside the noise. Home teams won 55% overall; Elo said 56%.
What we did. Left at 48, 538's number. Silver's ELWAY uses 1 to 3.5 points varying by team.
What would confirm it. Home teams winning a point or two less often than Elo says across the season.
What we found. Turning the QB adjustment off costs 357 points over three seasons, so it clearly matters. Raising the multiplier from 3.3 to 4.5 gained 13 points, inside the noise.
What we did. Left at 3.3. The side favored by a 25+ point QB adjustment won 56% of the time.
What would confirm it. Games with a big QB adjustment resolving toward the adjusted side more than Elo already expects.
What we found. Playoffs 2023-25: Elo Brier 0.199 vs market 0.212 over 39 games. Over 248 playoff games since 1999 they are level (Elo 1,610 points, market 1,617), and the blend at its normal weight beats both.
What we did. Nothing. A 75% Elo weighting in January was added on the 39-game result and removed when the long run disagreed.
What would confirm it. Only worth revisiting if Elo keeps beating the market in January for several more seasons.
What we found. Same home win rate, same calibration, and 70%+ favorites won 76% in division against 79% outside (288 divisional games).
What we did. Nothing, and nothing planned.
What would confirm it. Only worth revisiting if divisional favorites start losing more than forecast.
What we found. Of Elo's 60 worst misses, the median margin was 5 points and 26 were decided by a field goal or less. There is nothing to learn from those except to keep the slider off 90%.
What we did. Coin flips are their own spot on the Predictions page with advice to stay near 50.
What would confirm it. Nothing to confirm; it is a reminder.