By Michael Bond “If a car hire excess is £1000, and they’re going to charge me £50 for it, then I ask myself, am I really a 20:1 shot to crash this car?” How do you calculate odds? You analyse the teams or competitors with the stats you have available. For a Premier League football game, for example, you look at which team is better in the long run, which one has played better recently, where the game is being played, which players are available and any other factors such as how important this particular game is to each team. Having weighed up all these things, you come up with a probability that each team might win. How much is down to maths and how much to human judgement? We use algorithms and mathematical models, but very few bookmakers would generate prices and be confident of them using a computer program alone. You need human intervention to make sure everything has been taken into account. For the most part, the final figure comes from the trader’s head. This is what bookmaker traders do every day. They’re good at it. There are basic rules to follow. For example, in the Premier League, about 44 per cent of games are won by the home team, 26 per cent by the away team and 30 per cent are a draw. If you had two teams that looked as good as each other, then those are the percentages you would put on the match. That is your starting point. If you thought the home team was slightly better,