The gap between a team's position in the actual Premier League table and their position in the xG table is the strongest early-season predictive signal available. Teams significantly outperforming their xG (e.g., winning matches they "should have" drawn or lost based on chance quality) will regress downward. Teams significantly underperforming their xG will regress upward. Shot differential (shots for minus shots against) is the single most stable and predictive early-season metric — more so than xG itself in small samples because it's less sensitive to individual shot quality noise. The xG table "wins" over the actual table by March in 80%+ of seasons.
(1) After matchday 6-8, compute each team's actual points vs. xG-implied points. (2) Rank teams by the divergence (actual minus xG-implied). (3) The top overperformers (actual >> xG) are regression candidates — back their opponents in the next 10-15 matches. (4) The top underperformers (actual << xG) are value bets — back them before the market catches up. (5) Shot differential (xG-independent) can be used as a cross-check: if both xG table and shot differential agree a team is better than their results suggest, the signal is strongest.
In the first 6 matches of a season, raw shot differential (shots for minus shots against per match) is a more reliable predictor of end-of-season finishing position than xG differential. This is because xG models add noise through shot quality estimation in small samples — a team might have 5 high-xG shots that were actually well-defended, or 15 low-xG shots that were genuinely dangerous. Shot differential strips out the quality estimation and measures the more stable underlying driver: territorial dominance.
Generic "regression to xG" advice treats all overperformance as luck. But overperformance driven by elite set-piece coaching is structural and persistent — it doesn't regress because it's a genuine repeatable skill advantage. The market applies a blanket regression adjustment, creating value on teams whose overperformance is set-piece driven.