Reading it
The implied probability is 1 divided by the price, but those never sum to 100% across a market. The excess is the bookmaker's margin.
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
- Value betting guide — the method this term belongs to, start to finish.
- Football arbitrage guide — the same arithmetic, applied to two prices at once.
- Methodology — how the model is built and how well each market is priced.