The game uses 210 actual late-game starting situations and 34,367 eligible historical play outcomes from the 2024 nflverse play-by-play release.
Which facts are historical?
Opening score, possession, clock, down, distance, field position and timeouts come from recorded play-by-play. Skill-player names come from recorded participation in that game. The displayed 22-player formation is schematic.
How are later plays generated?
Eligible pass and run outcomes are grouped by broad play family, down, distance and field zone. Sparse groups fall back to larger pools. Tactical calls, personnel and defensive looks change sampling weights; selected historical yardage is retained. A sampled play may come from a different game. Penalty, kneel, spike and conversion plays are excluded from the historical outcome pool.
What is modeled rather than measured?
Named tactics, routes, defensive alignments, penalties, kicks, clock costs, animations and opponent choices use simplified models. Selecting a receiver does not apply an individual player rating. Animations are generated illustrations, not NFL tracking data.
What do the win estimates mean?
After a call, the game runs 192 simulated finishes per option. The resulting percentages describe this simulator and have sampling uncertainty. They are not actual NFL win probabilities, betting advice or a guarantee that one call wins.
How can the data processing be checked?
The source archive is play_by_play_2024.csv.gz. The recorded SHA-256 is 23370d5d10f8104d80d46a1fc5e61f4f6f5a3263fe96fe2dd629913cfcb08c06. The release contains a reproducibility script, scripts/prepare-football-data.py. Read the plain-text processing notes or download the original source archive.
Which sources support these explanations?
- nflverse 2024 play-by-play release — Historical opening situations and play outcomes.
- nflverse data dictionary — Definitions of down, distance, yardline, clock and outcome fields.
- nflverse CC BY 4.0 license — Attribution and reuse terms for the source data.
- NFL Football Operations rulebook — Official rules reference; this game deliberately uses simplified mechanics.
The data is attributed to nflverse under CC BY 4.0. It was transformed into compact samples and scenarios; nflverse has not endorsed this game. The NFL rulebook is a rules reference, not evidence that this simulator implements every rule.