∅ Empty Set Football
Week 15 · 2026 regular season

Chicago Bears at Buffalo Bills

Sat, Dec 19, 5:20 PM PT

Win probability
ESF
(win probability)
CHI 34%
66% BUF

No betting line yet. Lines appear once books post them.

Unit matchups · entering week 15

Where each side has the edge

Each offense against the defense it faces, in CAP yards per attempt. Offense: higher is better. Defense (yards allowed): lower is better.

Pass: CHI offense vs BUF defense
+0.359th
box score 7.4 · 13th
Edge
BUF
−0.615th
box score 7.0 allowed · 15th
Rush: CHI offense vs BUF defense
+0.429th
box score 4.4 · 12th
Edge
CHI
+0.1117th
box score 3.9 allowed · 11th
Pass: BUF offense vs CHI defense
+1.352nd
box score 8.7 · 1st
Edge
BUF
+0.9629th
box score 8.7 allowed · 32nd
Rush: BUF offense vs CHI defense
+0.605th
box score 4.8 · 4th
Edge
BUF
+0.3225th
box score 4.4 allowed · 22nd

CAP yards per attempt: yards per play relative to what the down, distance, field position and the specific opponent would predict; offense positive is good, defense (allowed) negative is good. Box score: yards per attempt as an official box score counts them, entering week 15.

CAP yards per attempt · 2026

How each matchup got here

Each unit's CAP yards per attempt entering each week. Offense: higher is better. Defense (yards allowed): lower is better. 0 is what the situation and opponent would predict.

CHI pass offense vs BUF pass defense
CHI pass offense BUF pass defense (allowed)
−0.8 −0.5 −0.3 0 +0.3 +0.5 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6wk 7wk 8 CHI +0.35 BUF −0.29 −0.8 −0.5 −0.3 0 +0.3 +0.5 0 = expected wk 1wk 3wk 6wk 8 CHI +0.35 BUF −0.29
BUF pass offense vs CHI pass defense
BUF pass offense CHI pass defense (allowed)
−0.3 0 +0.3 +0.5 +0.8 +1.0 +1.3 +1.5 +1.8 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6wk 7wk 8 BUF +1.40 CHI +0.96 −0.3 0 +0.3 +0.5 +0.8 +1.0 +1.3 +1.5 +1.8 0 = expected wk 1wk 3wk 6wk 8 BUF +1.40 CHI +0.96
CHI rush offense vs BUF rush defense
CHI rush offense BUF rush defense (allowed)
−0.3 0 +0.3 +0.5 +0.8 +1.0 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6wk 7wk 8 CHI +0.42 BUF +0.17 −0.3 0 +0.3 +0.5 +0.8 +1.0 0 = expected wk 1wk 3wk 6wk 8 CHI +0.42 BUF +0.17
BUF rush offense vs CHI rush defense
BUF rush offense CHI rush defense (allowed)
−0.3 0 +0.3 +0.5 +0.8 +1.0 0 = expected wk 1wk 2wk 3wk 4wk 5wk 6wk 7wk 8 BUF +0.63 CHI +0.32 −0.3 0 +0.3 +0.5 +0.8 +1.0 0 = expected wk 1wk 3wk 6wk 8 BUF +0.63 CHI +0.32
CAP win pct · 2026

How each team got here

CAP win pct entering each week. Higher is better; the league average is 0.50.

0.25 0.50 avg 0.75 1.00 1.25 wk 1wk 2wk 3wk 4wk 5wk 6wk 7wk 8 CHI 0.85 BUF 1.00 0.25 0.50 avg 0.75 1.00 1.25 wk 1wk 3wk 6wk 8 CHI 0.85 BUF 1.00
2026 results

Results so far

Each team's games before this one, with ESF's pre-game win probability for the team.

CHI Chicago Bears

WeekOpponentResultESF win prob
pre-game, this team
1 @ CAR Won 56%
2 vs MIN Lost 57%
3 vs PHI Won 47%
4 vs NYJ Won 81%
5 @ GB Lost 52%
6 @ ATL Won 54%
7 vs NE Won 53%

BUF Buffalo Bills

WeekOpponentResultESF win prob
pre-game, this team
1 @ HOU Won 38%
2 vs DET Won 69%
3 vs LAC Won 74%
4 vs NE Lost 70%
5 @ LA Won 49%
6 @ LV Won 74%
8 vs BAL Won 73%
Week 15

Other games this week

Home team's chance to win before kickoff. Higher means the home team is more likely to win.

Dots: ESF model home win probability.

How to read this page

CAP win pct. A fading average of game scores with a half-life of 7 of the team's own games. A win scores 1 plus the opponent's win pct; a loss scores the opponent's win pct minus 1. Last season carries in. League average is 0.50; higher is better.

CAP yards per attempt. Yards per play relative to what the down, distance, field position and the specific opponent would predict. Offense: higher is better. Defense (yards allowed): lower is better.

Box score yards per attempt. Yards divided by attempts, counted the way an official box score counts them: rushing includes scrambles and kneel-downs; passing is gross yards per pass attempt, sacks excluded.

ESF win probability. A logistic regression on both teams' pre-game CAP win pct, with an intercept for home field.