Slashdot Mirror
Computer System Makes Best Sports Bets
schliz writes to tell us that a new computer system using the "Logistic Regression Markov Chain" (LRMC) has proven to be the most efficient system at predicting sporting event outcomes. The system was tested on the 2008 US NCAA basketball season and picked all four of the finalists. "Similar to other rankings systems, LRMC uses the quality of each NCAA team's results and the strength of each team's schedule to rank teams. The method has been designed to use only basic scoreboard data, including which teams played, which team had home court advantage and the margin of victory."
The final four were also all #1s in their league. Coincidence? This has never happened before I believe and if the computer calculates odds the way the teams are ranked, then this may not always be so reliable.
The amount of noise involved strongly depends on which sport that is involved. Basket is a sport where a lot of points is scored, which in turn means that the noise is relatively low while football (what americans call soccer for some strange reason and what americans call football is more like rugby) has a lot of noise since the ability to score a goal there is depending a lot on luck.
This essentially means that counting points is a good way to score a basketball team while counting goals won't give much clue to how good a given football team is. You must look at other factors on a football team instead. And not all those factors can be as easily measured. Of course - the other factors are also important for a basket team. Other factors involved are the composition of players, individual player mood/health/inspiration, latest matches, history between the teams, referee behavior, weather, spectators, location, timezone etc. Add to this the element of randomness caused by the impact of the ball on a surface, player positions at certain points of the game etc.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
Here's the code I used
List pickFinalFour(Tournament tourney){
List finalFour = new ArrayList();
for (Division d : tourney){
Team bestTeam = null;
int minSeed = Integer.MAX_VALUE;
for (Team t : d){
if (t.getSeed()minSeed){
minSeed = t.getSeed();
minSeed = team;
}
}
finalFour.add(bestTeam);
}
return finalFour;
}
sigfault. core dumped.
One of our research assistants started doing something like this about ten years ago, fitting a statistical model to previous soccer match results and the home/away effect. He rounded some of us up to chip in a few pounds each week and off he went to the bookies to bet on the outcome of his model.
Now, any statistical model (such as this LRMC thing, or the techniques m'colleague used) will only give estimates of the odds. It might say that the probability of team A winning is 0.6. Now, if the bookies are offering you a return of 0.7 then it's worth a bet. If the bookies rate it 50-50 then it's not worth a bet.
The trouble is that any statistical model worth its salt is going to produce probabilities that add up to 1.0, whereas the bookies' odds can add up to 1.2 or so. That's how they play the game and make their profits.
So after a season where we made a few pennies profit, and got some press interest (including a team from BBC Tomorrow's World filming us playing football), my friend realised the best thing to do was not to bet at all.
And instead he went into the business of supplying odds to bookmakers. From where he now sits at the top of a rather large business empire!
I might pop him an email to see what his current techniques are, but back in the day it was something similar to this LRMC thing.
Why would 10 years be so much better than the 9 years they analyzed?
That's ok, becase I don't think that they created the algorithm with you in mind. You're just a negligible quantity.
Are you telling me that somebody actually looked at win/loss records and margin of victory and strength of opponents to figure out which team might win? How can this be? Why did nobody ever figure out this simple algorithm before? [slaps forehead with hand] DOH!
....
Oh wait, sorry it was patented years ago, and multiple times with minute variations such as going back to strength of opponents opponents, and margin of victory of opponents against common opponents, and strength of opponents opponents opponents, and
But if you add in what they ate for breakfast, then you might have a new patentable algorithm.
If I had a computer that could predict sports results, I wouldn't tell anyone about it. I'd take a briefcase full of cash down to the bookmakers.
I know this is Slashdot, but why can't people RTFA before commenting? They aren't using the seeds or rankings in the program - only game stats, home quart advantage, etc. They ran it on the last 9 years of data and it picked final four teams 30% more often than analysts. (30/36 vs 23/36).
The linked article didn't mention it, but from the GA Tech web site, it said that it correctly identified several overrated teams that lost early on (like Georgetown), and underrated teams that went farther than expected (like WVU). The program picks Kansas to win this year.
Doesn't say whether the test was done on in-sample or out-of-sample data. That is, did they test using the same data that was used during development?
If so, the results are worthless. You can make a "system" that says anything you want given enough tweaking. (This is often the problem with apparently successful computer trading models).
Great sample... They should test the algorithm on maybe 80 historical seasons and maybe we will be able to see something.
"We want this machine off, and we want it off now!"
But I can predict which team the machine will predict to win: Team #42
The Tao of math: The numbers you can count are not the real numbers.
I heard about this last year and used their picks for this year's bracket. I'm tied for first in my pool, and 93.5% nationally in espn's bracket game. Just for comparison of how good their choices are. They had 100% on the first round day one.
Here is the paper describing the method: http://www2.isye.gatech.edu/people/faculty/Joel_Sokol/ncaa.pdf