The System · Week 9
Ten rules, each with the number that earned it. Tested on 27 seasons, 1999–2025, 6,918 decided games: the 24 FiveThirtyEight published and every season Delta Sunday has replayed itself, refreshed as each week finishes. Per season over the 27: The System 1,011 points, the blend 1,003, the market alone 997, Elo 892. Against Elo that is 119 a season with a standard error of 19, ahead in 24 of 27 seasons: a real gap. Against the market it is 14 a season with a standard error of 10, ahead in 16 of 27: even, within the noise. And the rules were chosen on these same seasons, so treat the edge over the market as flattering; the seasons the site replayed itself went −16, +90 and +32.
- Start from the market. Over 27 seasons (1999–2025) the closing line scored 997 points a season; Elo scored 892.
- Add Elo at a quarter weight. A hair better than the market alone and it explains itself: quarterback changes, rest, the reasoning on every card. Half weight costs 17 a season.
- Nudge tight agreement by 2. Same favorite of 55% or more, within 4 points. Favorites there won 69.8% against a 67.6% forecast over 2,607 games. Small, but consistent across eras.
- Don't chase Elo's disagreements. Ten or more points apart, Elo's side won 50% while Elo claimed 65% and the market 48%, over 1,102 games. The quarter weight already handles it.
- Don't cap your confidence. Every cap tested cost points, in the long run and in the recent replays.
- Play coin flips at the number, not 50. Forcing 50 cost points.
- Playoffs: same blend. Elo and the market are level in January over 248 games. A heavier Elo weighting looked good on 39 recent games and did not hold.
- The lock gets the same 2-point nudge, no more. Locks won 85% (434-76) against a 79% forecast over 27 seasons. Pressing them by 5 cost points over 510 locks.
- Never skip a game. A skip is a 50/50 pick worth zero. Every System number expects positive points.
- Mind the weather, outdoors. Wind of 15 mph or more: favorites won 62% against a 65% forecast, so shrink toward 50 by a fifth. Fifty degrees or colder: favorites won 69% against 66%, so add 2. Over 75: shrink by a tenth. Together about 9 points a season over 24, positive in every era. Domes get nothing.
Every rule we tried beyond these cost points. The discipline is to play the numbers, and move one only when you know something the models don't: a late scratch, weather, a benching. The System is scored on every leaderboard next to the plain blend, so you can see whether the last two rules earn their keep this season.
| Game | The System | Why |
|---|---|---|
| JAX at BAL Thu 8:15 PM ET | JAX 00% | Jacksonville Jaguars over the Ravens: Elo 60%, market 79%. Big disagreement: trust the market number. Huntley is costing 16 Elo. |
| CIN at ATL Sun 9:30 AM ET | CIN 00% | Cincinnati Bengals over the Falcons: Elo 64%, market 60%. Tight agreement: go above both. Penix is worth 28 Elo; Burrow is worth 17 Elo. |
| NYJ at KC Sun 1:00 PM ET | KC 00% | Kansas City Chiefs over the Jets: Elo 79%, market 80%. Tight agreement: go above both. Mahomes is worth 46 Elo; Smith is worth 22 Elo. |
| DET at MIA Sun 1:00 PM ET | DET 00% | Detroit Lions over the Dolphins: Elo 59%, market 75%. Big disagreement: trust the market number. Willis is worth 90 Elo; wind 11 mph, 87°F (heat hurts favorites). |
| CLE at NO Sun 1:00 PM ET | NO 00% | New Orleans Saints over the Browns: Elo 53%, market 57%. Nothing to exploit; the blend is fine. Shough is costing 16 Elo; Watson is worth 34 Elo; NO off a bye. |
| DAL at IND Sun 1:00 PM ET | DAL 00% | Dallas Cowboys over the Colts: Elo 48%, market 70%. Big disagreement: trust the market number. Prescott is worth 17 Elo. |
| NYG at PHI Sun 1:00 PM ET | NYG 00% | New York Giants over the Eagles: Elo 53%, market 62%. Nothing to exploit; the blend is fine. McKee is costing 29 Elo; McCarthy is costing 88 Elo; NYG off a bye. |
| LAR at WSH Sun 1:00 PM ET | LAR 00% | Los Angeles Rams over the Commanders: Elo 60%, market 70%. Nothing to exploit; the blend is fine. |
| DEN at CAR Sun 1:00 PM ET | DEN 00% | Denver Broncos over the Panthers: Elo 63%, market 59%. Nothing to exploit; the blend is fine. CAR off a bye. |
| HOU at LAC Sun 4:05 PM ET | HOU 00% | Houston Texans over the Chargers: Elo 59%, market 65%. Nothing to exploit; the blend is fine. Herbert is worth 18 Elo; HOU off a bye. |
| GB at NE Sun 4:25 PM ET | NE 00% | New England Patriots over the Packers: Elo 63%, market 59%. Tight agreement: go above both. GB off a bye; wind 2 mph, 48°F (cold helps favorites). |
| LV at SF Sun 4:25 PM ET | SF 00% | San Francisco 49ers over the Raiders: Elo 77%, market 81%. Tight agreement: go above both. Cousins is worth 70 Elo; SF off a bye. |
| ARI at SEA Sun 4:25 PM ET | SEA 00% | Seattle Seahawks over the Cardinals: Elo 87%, market 84%. Tight agreement: go above both. Minshew is costing 87 Elo; wind 15 mph (matters), 60°F. |
| TB at CHI Sun 8:20 PM ET | CHI 70% featured this week | Chicago Bears over the Buccaneers: Elo 68%, market 68%, System 70%. Tight agreement: go above both. |
| BUF at MIN Mon 8:15 PM ET | BUF 00% | Buffalo Bills over the Vikings: Elo 37%, market 63%. Big disagreement: trust the market number. Murray is worth 100 Elo. |
If The System's numbers are right, it expects about 56.4 points this week.