Lorenzo Cascioli
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lorenzocascioli.bsky.social
Lorenzo Cascioli
@lorenzocascioli.bsky.social
PhD Student at @dtai-kuleuven.bsky.social
Yes, this definitely looks like a valid approach once you know which variables you want to control for! I guess it is a similar task to what was done here with multi-calibration dtai.cs.kuleuven.be/sports/blog/...
Biases in Expected Goals Models Confound Finishing Ability
Expected Goals (xG) has emerged as a popular tool for evaluating finishing skill in soccer analytics. Intuitively, the idea is dead simple.…
dtai.cs.kuleuven.be
May 5, 2025 at 10:40 AM
3️⃣ Interestingly, using features based on the 3 prior actions improves performance without introducing bias. This is likely because the features are team-agnostic.
April 24, 2025 at 9:26 AM
2️⃣ Other features in VAEP do not seem to introduce this bias as they do not record any global information about the current possession but only keep track of the last 3 actions.
April 24, 2025 at 9:26 AM
1️⃣ VAEP uses the current score difference in the game as a feature: this tends to slightly favor actions from stronger teams, but also improves predictive accuracy.
April 24, 2025 at 9:26 AM
All possession value frameworks describe the game state using slightly different sets of features. Some features can subtly act as a proxy for team strength (e.g., possession length), thus biasing action ratings for players on stronger teams. Here’s what we found 👇
April 24, 2025 at 9:26 AM