Change of course....

It's September already and I've realised that I've left this blog to die a slow and painful death. I'm pretty sure that everyone is wondering what happened to the system (and possibly myself) ... or maybe not! Anyway, work usually expands to fill available time, so there wasn't much time left to keep everything up-to-date.

The system resulted in significant losses (even though the yield was "only" -2.1%) as the following table shows:

I'm not going to post the remaining 200-or-so bets since the last update, but should anyone be interested enough, you can visit my thread at Punters' Lounge which also includes a small end-of-season analysis ...

What does the future hold? Well, I've been focusing on different modeling procedures, so I'll hopefully have some information on this in the not too distant future. Until then, take care!

The sorry state of affairs....

Well, it's been yet another hectic month with absolutely no update to the blog, and this has been a result of a couple of things: on the one hand, it's been a result of actually not getting any decent results (the demoralising factor), whereas it was the inevitable outcome of not having enough time for everything that needed my attention (the lack of time factor). Overall, these factors led to the current state of affairs.

Leaving decelopments in my personal life aside, it has been a yo-yo kind of month with the system fluctuating around the break-even point. In a discussion that I had with a fellow poster on Punters Lounge (where I have been updating my results for monitoring purposes), I accepted that I would have stopped posting the system's results had it not been for a promise I made to myself to follow the system through (on paper) until the end of the season.

Based on the above, and for anyone who keeps monitoring this blog (come back, I'll keep it updated, honest guv) the current state of play is as follows:

As you can see, after almost 900 bets the system is just about breaking even, which more than suggests to me that it's not finding betting value. I already have some ideas on what might be going wrong, and it's something that I will try to correct but this update will most probably take place during the summer. Of course, I'll keep updating it and monitoring its performance, since a promise is actually a promise...

System Update

It's been a long three weeks without a post! When you try to take too-many-things-at-the-same-time on, you are bound to fail unless you can cope with e 3-hour sleep every night... Anyway, between work, family and extra-curricular activities one would necessatily attract less attention, so it happened to be my blog. Apologies if anyone has been waiting for predicitions. I can say however, that I've probably saved you some money since the recent results have been hugely disappointing!

Anyway, I am not going to post all the selections up to now, but here is the latest system update:

As always, the record can be checked at Punter's Lounge where I've managed to post the system's selections in time. I'll (hopefully) be back tomorrow with the weekend predictions. Until then, take care!

Evaluating a Betting System's Performance (Part One)

It's been quite a while since I last had a blog entry which was not a system update so here is (hopefully) some food for thought.

Surfing the Internet, visiting various betting websites and forums (or should I say fora), I've stumbled across countless betting systems and strategies. These systems consist of not only the tipping part but also different, and sometimes quite elaborate staking plans. An obvious question which arises is "How does one compare these systems?"

I have always been a firm believer that forecasting / prediction models, irrespective of the way their predictions are formulated, should be monitored, evaluated and adjusted; in other words they should be judged. Only by judging a forecasting tool one can hope to improve it. What I am not exactly sure, and please if you have any views do share them, is the way this should be done. You see, everybody looks at the yield and of course this is a measure of how good the system is with this particular set of results. But it's also important to acknowledge that part of a system's performance is due to luck. In other words, if it was possible in a way to re-create all matches in a season, with the same parameters as at the time of the match, what would the system result in, given that not all matches would end up with the same outcome? Is there a way to utilize statistical theory in such a way to account for this uncertainty an create a more robust measure than yield itself? The million dollar question, I guess.

Internet research on this issue leads quite often to the notion of χ²-testing. The idea behind this test is to compare, with some sort of statistical confidence, the number of a system's actual (or observed) winners to the corresponding expected number. For example 15 bets at even odds would yield an expected number of 7.5 winners, but the actual number of winning bets might be 9. Is this sufficient evidence to suggest that the system is performing better than what would be expected by sheer chance? What if the actual winners were 10? 12? All 15?

Well, the χ²-test provides a way to measure this by looking at the probability of achieving the observed result (i.e. the number of actual winners) or a better result by chance. If for example there is a 30% probability of hitting 9 winners or more (given the odds at which the bets were taken) out of 15 simply by chance then the system is not performing necessarily well. As soon however, as this figure is reduced, it means that the system is hitting the winners not necessarily by chance but rather by exploiting value through mis-priced matches. Anyone who has studied any introductory statistics course will tell you that the figure that statisticians are interested in, when testing hypotheses, is the 5% so in effect, according to this test, one would be happy if the χ²-test returned a probability less than 5%.

My personal opinion is that the χ²-test is not necessarily a good indicator of whether the system is performing well. All it does is to check whether the number of winners is significantly higher than what one would expect by sheer chance, but it does not consider the odds at which these winners were picked. What if a system's winners came at very low odds, whereas the system underperformed in the high range of odds. This could lead to a case of achieving a high (as compared to the expected) level of winners, yet the yield could be very low or even negative! Some consolation, I hear you say ... Of course the opposite could also be true: a few longshot winners could be enough to lead to a positive yield yet the number of correct picks could be below the expected number. [For the doubters amongst you that such a case is not as implausible as it may sound, feel free to check the relevant discussion on Punters' Paradise forum.]

The search must carry on. In Part Two of this post (to be posted some time in the near future), I'll look into different ways of assessing whether one has a profitable system and to evaluate its performance. Until then take care!