Method of determining value

[Guest Drive Blind]

A method for winning at football betting. How? Only bet when you have a value bet of course, and in the long run you will profit. Sounds easy does'nt it. Every gambling book on the market and countless posts here will tell you the same. How do you know know when you have got a value bet? One way is to analyse the press, team news, injuries, suspensions etc.. There are literally hundreds of parameters you could use to give you confidence. You will never really get a precise nature though of the edge you will have on each bet. One way to indicate the stength of a teams chances is by using some kind of rating system (Rateform) etc. Using statistical methods to rate a teams future performance is probably a good way to go if you are prone to letting your heart rule your head or just plain not very good at analysing these variables. Probably the best rating system out there, which is very profitable and very accurate are the bookmakers odds themselves. Why not let the odds setters do all the hard work of analysing hundreds of parameters. The computers analyse all of this data and publish it every wednesday in a bookie near you! Just pick up the fixed odds sheets everyweek for the stats. The odds are pretty much very consistant. Using Joes spreadsheets :- Home teams where the odds are 1.33 win 72% of the time. Home teams where the odds are 2.0 win 46% of the time. Home teams where the odds are 3.0 win 22% of the time. In the example where a team is priced up at even money with say Ladbrokes, their true chance of winning on past examples is 46%. This means we will need a price of 2.17 at least to break even. Add on a profit margin and request the value price on Betfair, if the bet is matched then, wahey! we have a value bet. If it is'nt then we don't need to worry as we know that we will not break even over the long run at the price being offered. What profit margin should we add on to our break even price ? We need to consider the favourite-longshot bias here. Shorter priced teams are generally closer to the true chance of them winning, so we would only add on say 5-10%. For outsiders, we could ask for more margin. Using this method allows us to literally request odds on every single match, if we get them matched then statistically based on previous results we should be ahead in the long term. What is encouraging is that the odds the bookies offer and the true chance of the team winning are remarkably consistant over time. Sure the bookies don't get it right all the time, but they do most of the time. Any thoughts to this method ?

[dave]

Interesting Very interesting thoughts. A couple of points. 1) How would you decide which bookies odds to use? Are the true chances of a 1.33 shot winning the same for all bookies. I assume not, though you have access to the data, so perhaps you could look into that. 2) You would have to take into account not only the profit margin, but also the commission rate on betfair.