Fourth Down Calculator

About this Project

Fourth Down Calculator compares going for it, kicking a field goal, and punting by expected win probability. Users can build a hypothetical situation or select an NFL game and load a real fourth-down play, then compare the model’s recommendation with the team’s actual decision and the play’s outcome.

I trained custom win-probability models on historical NFL play-by-play: a regulation model using game situation and pregame market expectations, and a dedicated overtime model that accounts for possession order, earlier scoring, and overtime rules. Regulation estimates split the chance of reaching overtime equally between the teams. The calculator combines these predictions with nfl4th conversion, kicking, and punt outcome estimates, plus matchup, kicker, weather, and kickoff adjustments.

The React and TypeScript frontend runs calculations in a browser Web Worker. A Python data pipeline processes nflverse play-by-play into team and kicker ratings and a browsable archive of real game situations. The current archive covers games from the 2024–2026 seasons.

This is an ongoing personal project. I’m continuing to refine the model and its evaluation; historical plays are explored using the current ratings, rather than ratings reconstructed as of each game.