# Rules and simulation method

Updated: 2026-10-24

Rules version: clutch-match-2.0.0

Outcome model: empirical-2023-v1

## Clock and downs

- A default no-huddle running-clock call uses 10 seconds of setup. A stopped-clock call charges 0 setup seconds to the game clock.
- A running-clock spike uses 6 setup seconds and 1 live second, and spends a down. A fourth-down spike gives up possession.
- An eligible timeout stops the clock without using a down. The same dead ball cannot be charged twice.
- Incompletions and out-of-bounds finishes stop the clock until the next snap in this model. Inbounds first downs renew the downs and leave the clock running.
- A field goal is modeled as yards to the goal line plus 18. It is available at 55 modeled yards or shorter, adds three points if made and ends the possession either way.

## Evidence and limits

The outcome model pools penalty-free late-game plays from the 2023 nflverse play-by-play release. The 2024 records supply historical starts and held-out descriptive checks. Setup and live-play durations are declared design assumptions. FTN tactical tags, pressure and field-context cells refine supported samples. Weekly roster choices use prior-game production with bounded design adjustments; sparse samples remain uncertain. This is not a calibrated individual-player forecast.

Decision feedback compares bounded complete-game simulations for available calls with paired seeds under a contextual policy. Its percentages describe simulated full-game win chance, including opponent replies and overtime, not a measured NFL forecast. Sampling intervals do not include uncertainty in the model assumptions.

[Full method and scoring limits](https://twominuteclutch.com/methodology) · [Sources and licensing](https://twominuteclutch.com/data-sources) · [2026 NFL Rulebook](https://operations.nfl.com/rules-officiating/2026-nfl-rulebook)

## Guide examples

Guide clock tables use chosen outcomes and the game engine. They are controlled teaching examples, not recorded historical plays or forecasts.