After each game, a team's performance can be described by the final score or by the team's expected goals percentage (xGF%). These two stories usually agree, but not always. A team can generate the larger share of quality scoring chances and still lose, or generate the smaller share and still win. A mismatch between these two measures does not mean much for a single game; however, a persistent gap over the course of a season is a meaningful signal. In general, we expect large deviations to narrow over time, similar to a regression to the mean.

The Chip Share Ledger is a tool built to track that gap. It is a zero-sum accounting of a team's season, treating each game as two even-money wagers. One wager is settled by actual results, the other settled by xG.

• Each team starts the season with 82 light blue chips (xG Win Chips) and 82 dark blue chips (Actual Win Chips).
• Each game, both teams wager one chip of each color.
• The team with the higher xG collects both light blue chips.
• The winner of the game collects both dark blue chips.

This results in a closed economy, where chips are redistributed but never created or destroyed. This enables us to compare chip totals, trends, and deviations across seasons.