Win probability (WP) is a number that represents a team’s chances of winning. It was originally created by Pro Football Reference (the OGs of advanced statistics) although there are some slightly different versions in use today. Win probability is determined by a formula that takes into account things such as team strength, current score, time left, field position, possession, and down & distance. Essentially, it creates a chart of how a team’s chances of winning ebb and flow (or peak and plummet) with the results from one play to the next. Each week, the WP is charted for every NFL game by numberFire, ESPN, and Lee Sharpe.
The Buffalo Bills started Week 4 with anywhere from a 51-65% WP, depending on your chart of choice. Only one WP even ever gave the Las Vegas Raiders a WP over 50% the entire game and it peaked at 53% on the Bills’ first drive while the game was scoreless. The entire rest of the game, the Bills were in control, both in the minds of fans and in the conclusion of the WP algorithms.
Here are some images of what the Bills vs. Raiders WP charts looked like after Sunday’s game.
Win Probability: Bills @ Raiders pic.twitter.com/HfAaHzfbWh— Lee Sharpe, ⛓️ @ (@LeeSharpeNFL) October 4, 2020
Compared to last week’s game against the Los Angeles Rams, this was a ride on a freshly paved portion on highway. Even when the Raiders came within one point with around 6:30 left to play in the third quarter, the Raiders never crossed into being over 50% WP on any chart.
Perhaps the most interesting and influential moment in the game according to WP was the incredible one-man show put on by Josh Norman with his forced fumble and recovery. Time is such an influential part of WP that Norman’s play is more consequential simply because it happened where it did rather than earlier in the game. With just under 13 minutes left in the game, that play ranged from +9% to +12% for the Bills and put them into the mid to high 80s% WP. The Bills cracked the 90s on the very next play with quarterback Josh Allen hitting wide receiver Stefon Diggs on a 49-yard bomb to take the Bills to the Las Vegas 11-yard line.
From there, it was no looking back. The Bills bounced around in the mid-90s until the Raiders turned it over on downs when Josh Jacobs got stuffed on a 4th-and-1 and the Bills rocketed to 99% WP with 9:47 left in the game. Nothing moves the needle more than 4% over the remaining drives as the Bills grabbed their fourth win.