BETTING BASICS / EXPECTED VALUE

What does positive EV mean?

Expected value, or EV, describes the average net result of a bet under an assumed probability. Positive EV means the offered payout is favorable under that estimate. The important word is estimate.

An estimate of value, not the next result.

A positive EV bet can lose. A sequence of positive EV bets can also lose, even when the probability estimate is reasonable. If the estimated probability is wrong, an apparent edge may not exist at all.

The +5% figure is not a 5% chance of winning, a guaranteed $5 return, or a forecast of account growth. It depends on the assumed probability, offered price, fees and settlement rules.

Where does PropGoat’s estimate come from?

In Independent mode, you choose one or more reference books; each produces its own qualifying comparisons, including props covered by only one book. PropGoat uses both opposing reference prices at the same line and removes their combined margin proportionally. This de-vig process produces each reference probability. In optional weighted Consensus mode, valid reference probabilities are blended using your weights, required-book settings and minimum coverage. The combined EV and minimum number of references individually meeting your EV threshold must both pass. The target sportsbook is excluded from its own blend. See the Consensus setup and examples.

For a simple example, −110 on each side implies roughly 52.38% per side, totaling 104.76%. Proportional de-vigging normalizes the two estimates to 50% each. The result describes the reference market after that adjustment; it does not prove the true probability is 50%.

What does “fair price” mean on the board?

Fair price expresses the reference-derived probability as odds without the reference market’s combined margin. It is a useful comparison point, not an objectively correct price. Changing the reference book or the underlying quotes can change the estimate.

Displayed fair odds are rounded. The EV calculation uses the underlying probability, so recalculating from the rounded fair price can give a slightly different percentage.

Why might an estimate be missing?

A reliable comparison requires matching reference sides and a usable offer. Missing opposing prices, incomplete pairs, unsupported push lines, reference-quality checks or unknown fees can prevent an EV estimate. Prices may still be visible for ordinary comparison.

Known fees are included in EV ranking, while displayed odds remain the advertised odds. Do not assume two books with the same visible price have the same net payout after fees.

Use EV as context.

Check the matchup, market, line, reference and collection time. Verify the actual offer at the sportsbook, and consider whether its rules and fees match the comparison. A larger displayed percentage can reflect an unusual or stale quote rather than a stronger opportunity.

PropGoat provides research tools, not guaranteed wins or personal staking advice. Start with the basics of line shopping, keep your decisions within a budget you can afford to lose, and treat the displayed edge as an estimate to evaluate.