As nearly every professional bettor will tell you, backing heavy favourites is a sure fire way to the poorhouse. That is common knowledge, right? Perhaps, but there's one problem with that sort of thinking: it's dead wrong.

The received wisdom is the linesmakers skew their odds on heavy favourites because the public love betting on the best teams. The bookies no doubt see a flurry of parlays involving clubs like Chelsea, Barcelona and Juventus every weekend. Surely there's value in taking the underdog in these situations, online casino is not there?

The truth is, numerous research has shown that blindly backing long shots is a losing proposition within the long-term. To determine why that is the case, we have to understand how a bookmaker operates. Since the bookies take most of their action on short-priced favourites, it's often assumed they may be exposed to big liabilities if all the hot teams win. While this is sometimes the case, and several bookmakers suffer months of huge losses, you can find a number of ways a bookie can protect himself.

It is important to take into account that most heavy favourites are combined in parlays involving at least three teams. A bookmaker only needs one loser to take his customer's money. As such, there's little need to lower the odds on a "public" team. Many sportsbooks will even inflate the odds of a hot favourite to attract new customers, safe within the knowledge that parlay players won't hurt their bottom line.

In the event the favourite's odds are an accurate reflection of it's true probability of winning, the bookmaker must make adjustments elsewhere. That usually means offering worse odds on the underdog and the draw. Comprehending the concept of theoretical hold can make this clearer.

When creating lines, a sportsbook will offer odds on each team which provide it a slight edge, ensuring a profit irrespective of how the game turns out. This is called the Theoretical Hold and is expressed as a share. It represents the combined quantity of customers' bets that the bookmaker expects to keep.

It's called theoretical because in reality a bookmaker rarely has balanced action on all sides. If a bookie takes the bulk of his bets on a heavy favourite, he can offer it at a more generous price and accept a smaller profit margin. Short-priced favourites generally have small margins, but high volumes. Bigger odds mean bigger margins. There's little incentive for a bookie to offer competitive odds on a big underdog if he doesn't expect much betting interest in that team.