Fair Line: The Books' Average View of a Prop
How it is built
Each book prices an over and an under. Remove the margin from each pair, as in the no-vig page, and average the results across books at the shared number. A pair of -115 and -105 gives 51.1% for the over. Another book at the same number may say 50% or 52%; the fair line is the average.
- Over, margin removed
- 51.08%
- Under, margin removed
- 48.92%
- Fair price for the over
- -104
What it is for
On the boards, a player's hit rate is shown beside the fair line instead of beside 50%. A 70% hit rate against a 65% fair line is a smaller story than against 50%. The fair line is the market's view. It is not Probetrics' prediction and it is not advice.
A prop with only one side priced, such as an anytime touchdown, has no fair line, because there is no opposite side to remove the margin against.
Questions and answers
- Is the fair line the true chance?
- No. It is the books' average view with the margin removed. It can be wrong.
- Why does a prop show no fair line?
- Fewer than two comparable prices, or a one-sided market, means there is nothing to remove the margin against.
- Is the fair line your prediction?
- No. Probetrics does not publish its own probability for player props. The fair line is the market's.
Read next
- No-vig oddsNo-vig odds, also called fair odds, are a two-sided price with the sportsbook's margin (the vig, or juice) taken out, so the two sides' chances add up to 100%.
- Hit rateA hit rate is the share of a player's games that finished on one side of a prop line, and over a small sample it is a wide range rather than a single number, which a Wilson interval makes visible.
- Player prop lineA player prop line is the number a sportsbook posts for one player's stat in one game, such as 24.5 points, with a price on the over and a price on the under.
- Implied probabilityImplied probability is the chance a price says an outcome has, found by converting the odds, and it puts American, decimal and fractional prices on one 0 to 100% scale.
This page explains arithmetic and vocabulary. It does not recommend a bet, a side, an amount or a sportsbook, and the examples are illustrations. For information only, not betting advice. 21+ only. Gambling problem? Call or text 1-800-GAMBLER.