About

Sporacle is a free NFL decision service and a calibration research project.

How the numbers are made

Two models produce everything on this site. The first predicts the margin of each game as a distribution, which is where the win likelihood and the projected score both come from. The second projects player usage first and per opportunity efficiency second, which is deliberate: how often a coach uses a player is fairly predictable, while yards per touch is close to noise week to week. Keeping them separate stops a hot week from being mistaken for a change in role.

Explanations are written once per weekly run and cached. They describe the numbers the models produced and are not permitted to introduce facts of their own.

Provenance

Every number we publish carries a label saying where it came from: a model reading current data, a prior built from last season, an imputed input, a placeholder, or a stale carryover. When you see a badge on a number, that is this system telling you the number is not a live model read. Nothing on this site is allowed to be published without one of those labels, and no external source's number is ever republished as ours.

Data sources

• nflverse, the backbone: play by play, weekly stats, snap counts, depth charts, injury reports, rosters and schedules. Community maintained and open, and gratefully used.
• ESPN public API for live game state and freshness checks.
• Open-Meteo for weather at kickoff windows for outdoor games. Weather is left empty for indoor games rather than guessed.
• A hand maintained table of the 32 stadiums for location, altitude, roof and surface. Those coordinates are approximate and marked as unverified in our own data until we replace them with a sourced table.

We use no team logos or marks. Team names and scores are facts and are used as such.

Honesty commitments

• A published prediction is never edited or deleted after kickoff. Corrections are dated annotations.
• Misses appear next to hits on the track record page, uncorrected.
• No statistic appears here that did not come out of the pipeline.
• No betting framing, ever: no picks, no odds, no edge claims.