The Favourite-Longshot Bias: Why Long Odds Often Cost More

The favourite-longshot bias is a pattern seen in many betting markets: outsiders tend to be priced less generously than their real chances justify, while favourites are priced closer to fair. Put simply, the bookmaker's margin is not spread evenly. A long shot at big odds often carries a larger share of it than a short-priced favourite does. The pattern has been discussed for decades, particularly in horse racing, and it helps explain why long prices can be among the most expensive bets on a board.

It does not mean favourites are good value or that outsiders never win. It means the price of hope is usually higher than the price of a likely result.

What the bias looks like

Imagine an invented race in which every runner's price is converted into an implied probability. If the market were perfectly fair, a runner priced at 20% would win about one race in five over many similar races. Under the favourite-longshot bias:

• Runners priced as heavy favourites win roughly as often as their prices suggest, sometimes a little more.
• Runners priced as rank outsiders win noticeably less often than their prices suggest.
• The gap grows as the odds lengthen.

So two bets that both "contain" the same overall market margin can carry very different costs depending on where they sit in the price range. If converting odds into percentages is unfamiliar, our explainer on the vig walks through the method.

Why it happens

Several explanations are offered, and more than one may apply at the same time:

The chasing explanation links to a wider pattern: when frustration drives the next bet, long odds become more attractive precisely when judgment is weakest. Our article on being on tilt describes that state.

Where it shows up

Racing

Horse and greyhound racing are the classic settings, with big fields and many outsiders.

Outright and futures markets

Season-long markets on who will win a league or tournament often list dozens of names at long prices. The total margin on these markets tends to be large, and much of it sits on the outsiders.

Novelty and prop markets

Unusual outcomes at big prices, such as an unlikely player scoring first, are another place where the cost can hide. Our guide to prop bets covers why these markets are often priced with a wide cushion.

Slots and jackpots

Slot games are not priced by markets, but a similar feeling applies: the rare top prize gets the attention, while the everyday cost is set by the return-to-player figure.

What it means for bettors

1. A long price is not a bargain by default. The bigger the number, the more likely it hides a heavier charge.
2. Combining long shots multiplies the effect. Multi-leg tickets made of outsiders stack the extra cost leg by leg.
3. Closing prices tell part of the story. Comparing your price with the final one, as explained in closing line value, is affected by this bias at the long end.
4. Entertainment value has a price. If the thrill of a long shot is the point, treat the extra cost as part of the ticket price rather than an opportunity.

Is the bias always present?

Not in every market or every period. Its size varies between sports, between operators and over time, and in some markets it has been reported to shrink or even reverse. Treat it as a tendency worth knowing about rather than a fixed rule.

Frequently asked questions

Does this mean only betting on favourites is smart?

No. Favourites still carry a margin, and a bettor backing only favourites is still paying the bookmaker's fee on every bet. The bias changes how the cost is distributed, not whether there is one.

Is a long shot ever good value?

Occasionally prices can be generous, but nobody can know that reliably in advance. Assuming value at big prices is one of the more expensive habits in betting.

Long shots are part of the fun for many adults who bet, but the fun has a cost that grows with the odds. Check that betting is allowed where you are, and keep any long-odds flutter small enough to forget about once it loses.