Friday, 1 June 2012

Winners Mean Business

BigAl did actually make a good point in his last comment, writing:

If I can raise a point. 
You often justify your ideas with "average prices". I hope you can see that this is a dangerous approach. I suppose in simple terms, its only the price of the winners which count when you're analysing the final returns of this type of stuff. The returns of the winners in the data for which you don't have prices could conceivably be low enough to produce a negative ROI even if the average price were to be what you think.
To be fair, your xx draw prices are fairly constant due to the similar type of matches you pick but you have indirectly picked up on the above issue with your comments on the Italian results.
Sensible points and constructive criticism are always welcome here. To give an extreme example to show BigAl's point, six draw selections at 5.0, 5.0, 4.0, 4.0, 3.0 and 3.0 gives a (mean) average of 4.0, but if the two winners were the 3.0 matches, it's clearly a wrong approach. I have the draw prices for 225 matches going back to 1.Jan.2011 and while the price on winning draws is, as might be expected, shorter than the (mean) average price, it's not by much. In fact, two leagues had the average price of winning draws at a longer price than the mean average. 

However, it would be more conservative for me to err on the side of caution when making my projections, and use the median averages. For those interested, and we all should be, the numbers across all leagues for the draw prices are:

In England and Spain, the price of winners is longer than both averages, whereas in France, Germany and Italy expectations are met, and the winners are slightly shorter than the averages. While a healthy 72 of those 225 matches were draws, 72 spread over 5 leagues means that each sample size is still small. These numbers will become more reliable as time goes on. As BigAl also commented, data mining can be an issue if you drill too deep with a small sample.

For example, are 126 selections enough to determine that the Bundesliga selections should be excluded for the Extended selections? For me, yes - because there is a reason why these results are disappointing. But surely this also means that the Bundesliga should be excluded from the Classic selection too? For now they have the benefit of the doubt, but it's more likely that the Bundesliga will be removed from the XX Draws altogether, than that they will be added to the Extended.

The Leagues I follow were chosen because they had the top 5 UEFA rankings, and because they were Football Elite's leagues also. Atill waiting for news of my Clacton trip incidentally. Portugal recently replaced France in that list, and I'm thinking of including the Portuguese Liga from next season, on probation. There are also some leagues in Eastern Europe that I have my eye on - Slovakia has a low average goals per game at 2.29 last season 2.19 before that, with 27% and 30% draws respectively. Unfortunately, I know nothing about Slovakian football, but 23.7% of matches ending 0-0 or 1-1 sets my pulse racing. That's even higher than Ligue 1 (22.9%).    

Anyway, thanks to BigAl for the helpful comment, and the prospectus has been updated to reflect the median and winning prices, and a thank you to George for spotting an error on the Stoke City v Everton game on May 1st which has now been corrected.

1 comment:

AL said...


will there be a EURO2012 XX Draws selections?

AL (Little)