Bridge has truly hit the big time. No, I do not mean bridge has been admitted to the Olympic Games. However, bridge is now listed on at least two sports betting sites! The sites are PAF, www.paf.com/betting, an organisation with offices in Finland, Sweden, Estonia and Spain, and Unibet, a Spanish betting site resident in Malta at https://es.unibet.com/betting and the Bermuda Bowl is the game. Italy is, no surprise, the favourite at 2:1; on both sites USA1 is next at 13:4 and 4:1 respectively.
Sweden, The Netherlands and Poland are listed at 15:2, 8:1 17:2 on PAF and all three are at 15:2 on Unibet; USA2 is at 10:1 and 15:1 respectively; Brazil and Israel are at 12:1 on both sites and Bulgaria is at 15:1. China is at 25:1 and Egypt, India and Iceland are at 75:1. Everyone else goes off at 500:1.
While you may believe that, for example, Bulgaria is a better bet than Israel, thefact of the matter is that these are very realistic odds, at least in relation to one another. However, there is a caveat – the “vigorish”, the amount charged by the bookmaker for his services. In North American football, for example, if you lose a $100 bet, you pay off at $110, but win at $100. That is 10% of the losing bets or 5% of the sum of the bets, a very reasonable proposition for the punter. And, what’s more, the vigorish is quite transparent.
It’s quite a different matter for “league” betting, when you bet on one of manyteams to win a league (e.g., the Bermuda Bowl) and the vigorish is hidden in the odds. There, to calculate the vigorish, you need a basic knowledge of the relation that odds have to probability. It’s really quite simple: odds of 4:1 mean that the bookmaker has that team winning one in five times (4 times losing:1 time winning, thus one out of five times). To calculate the vigorish, the first step is to convert the odds to probability. The probability of all teams winning a league (in the real world) sums to 1, or certainty. The amount that the total team probabilities add to more than 1 (in the bookmaking world) is called the amount “over the round” and amounts to the vigorish.
In our Unibet Bermuda Bowl league, for example, Italy at 2:1 translates to a probability of their winning of 0.33 (one in three times). USA1 is 4:1 (one in five) or 0.20; Netherlands, Poland and Sweden at 15:2 are 0.118 and so on.
The next step is to add up all the probabilities for each team. In a true odds/probabilty world, the probabilities would add to 1. In our Unibet world the Bermuda Bowl probabilities add up to 1.257. Thus the bookmaker (assuming a balanced ledger, always a dicey proposition) makes approximately 25% on the total amount bet. This makes league betting a very poor proposition for the punter, but the average punter hasn’t the knowledge or the patience to calculate the true odds.
The betting public in Great Britain, in general, is much more knowledgeable about the true odds on betting than are we North Americans, and would not put up with league betting in the USA, where a vigorish of 50% is not unusual. In England, the amount over the round is more likely to be in the 12-15% range.
(IBPA Bulletin 2011, October)