Reading it
Poisson assumes the variance equals the mean. Fouls and tackles are more spread out than that, and a Poisson would systematically put too little probability on the high scores — which is precisely where over bets live.
Definitions describe what Per90’s licensed data feed records, which is not always what a given bookmaker settles on. When the two differ, the bookmaker’s rules decide a bet.
Where it appears on Per90
- Player props research guide — the method this term belongs to, start to finish.
- Methodology — how the model is built and how well each market is priced.