The favourite-longshot bias is one of the oldest and most studied patterns in betting markets. In simple terms, it describes the tendency for long-priced outsiders to be backed more heavily than their real chances justify, while short-priced favourites are slightly underbacked relative to how often they actually win.
The reason is largely human. A small stake on a big outsider offers the dream of a large payout, and that appeal draws money toward longshots regardless of the underlying odds. Favourites, by contrast, feel dull — winning a modest amount on a likely result lacks the same thrill, so they attract proportionally less support.
The practical effect is that the prices on heavy outsiders are often shorter than they ought to be, quietly eroding their value, while favourites can occasionally offer marginally fairer prices than the crowd’s behaviour would suggest.
This does not mean you should mechanically back every favourite. The bias is a tendency, not a guarantee, and it varies from sport to sport and market to market. What it should do is make you cautious about chasing big-priced dreams purely because the payout looks exciting. As always, the right question is whether the price genuinely beats the true probability, not whether the potential return looks impressive on the slip.
18+ · Gamble responsibly · /responsible-gambling/