Every game was priced from real bookmaker moneylines pulled from the historical odds archive, then de-vigged so the two sides add to 100%. That de-vigged number is the market's honest win probability. A factor only counts as an edge if games matching it beat that probability by more than chance would explain. Real surface, roof and stadium recorded for every game from the historical venue data. Games grouped by surface, by roof type, and by altitude venue, including the specific case of visitors in Denver. Each group's real win rate compared with the summed de-vigged market probability for those same games.

edge lab · factor writeup · 6 min read

Surface and Altitude: Turf, Grass and the Denver Myth

Q: What the numbers said

Sample: 5,295 games; Window: 2006–2025; Signal: z < 1.17 Every venue split came back inside noise. The Denver Broncos' home advantage is genuinely a little larger than average — and the market prices Denver home games with a slightly larger home edge. The effect is real and the discount is not. The pattern by now: Five factors, five flat results, one reason: the closing line is the aggregated opinion of everyone who has already thought of your idea.

Q: What it means for your picks

Surface and altitude are not tiebreakers. Weather, by contrast, is at least worth understanding, because it changes how games are played even when it does not change who wins — that analysis lives on the weather page, and every venue's real scoring history is in the stadium guide. The full register is in the Edge Lab.

Playing surface and Denver's thin air are the two venue effects everyone cites. Across 5,295 games, both are fully absorbed by the market.

Two venue stories get repeated every season: teams built for turf struggle on grass, and visitors wilt in Denver's altitude. One of them has real physiology behind it. Neither of them is worth a pick.

What we tested

The hypothesis: playing surface (turf versus grass), roof type, and high-altitude venues create outcomes the market systematically misprices.

How we tested it

Every game was priced from real bookmaker moneylines pulled from the historical odds archive, then de-vigged so the two sides add to 100%. That de-vigged number is the market's honest win probability. A factor only counts as an edge if games matching it beat that probability by more than chance would explain.

Real surface, roof and stadium recorded for every game from the historical venue data.
Games grouped by surface, by roof type, and by altitude venue, including the specific case of visitors in Denver.
Each group's real win rate compared with the summed de-vigged market probability for those same games.

What the numbers said

Sample: 5,295 games
Window: 2006–2025
Signal: z < 1.17

Every venue split came back inside noise. The Denver Broncos' home advantage is genuinely a little larger than average — and the market prices Denver home games with a slightly larger home edge. The effect is real and the discount is not.

The pattern by now

Five factors, five flat results, one reason: the closing line is the aggregated opinion of everyone who has already thought of your idea.

What it means for your picks

Surface and altitude are not tiebreakers. Weather, by contrast, is at least worth understanding, because it changes how games are played even when it does not change who wins — that analysis lives on the weather page, and every venue's real scoring history is in the stadium guide.

The full register is in the Edge Lab.

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