Home teams score more and concede fewer than the same teams away — historically worth around 0.3–0.4 goals per match, driven by crowd effects on players and referees, travel, and familiarity. The effect is real, league-specific, and slowly shrinking across football.
Every serious model carries separate home and away rates rather than one team strength; ours does. The betting angle is not that home advantage exists — the market knows — but that its SIZE varies by league and season, and prices set on the global average misprice the extremes.
In our fitted leagues the home goal rate runs ~1.4 vs ~1.1 away — a 0.3-goal edge worth roughly 8–10 points of win probability in an even matchup. A league whose current season runs materially above or below its own average is where the totals and 1X2 prices drift wrong first.