Do favorites continue their dominance in '06 NFL?

GiftGiver · #1 08-29-2006, 02:07 AM

As many of you know, favorites in the NFL covered at a rate of about 57% last year. Which is the highest rate ever. Do you think that will continue in 2006?

The NFL looks today like it is full of 10-11 win teams and 5-6 win teams without too many in the middle. Parity seems to be gone for the time being.

Most sucessful NFL handicappers have for years used the contrarian approach of betting mostly dogs and going against the public. Do you think that this strategy will fall flat on its face like in 2005?

Levarkin · #2 08-29-2006, 02:21 AM

Perhaps there's an explanation here I'm not aware of, but I saw the unusual success of favourites in 2005 as a statistical aberration, and nothing more. Thus, I consider it no more or less likely that favourites will do better than usual this year. I don't see what effect parity has. I can understand a wider range of spreads as a result, but not why favourites would be any more likely to cover.

Edit: An interesting note from the Wizard of Odds, who - like most cappers - had a rough '05:

"During the 2005 regular season favorites beat the spread 144 times, underdogs covered 103 times, and 9 times the game fell exactly on the spread (according to Mr. NFL spreads). The probability of underdogs doing so badly assuming a 50/50 chance of winning over 247 resolved bets is 0.45%, of 1 in 220."

I notice that the Wiz tracks performance against the spread back to 1983. In 24 seasons, the odds of a 1 in 220 shot hitting are around 9-1. So while it's possible that bookies were just chronically underestimating favoured teams, the statistical explanation isn't entirely inplausible. And even if it is the former (which I doubt), you can certainly expect a correction, as many books take a significant hit when favourites do so well.

In other words, I wouldn't bet all faves this year and expect to cruise to easy money.

RikaKazak · #3 08-29-2006, 07:46 AM

good analysis lev

NajdorfDefense · #4 08-29-2006, 11:18 AM

No.

Levarkin · #5 08-29-2006, 05:12 PM

I'd actually like to re-open this debate if anyone is interested. I was basing my thoughts on the WOO's analysis, and he's certainly right about the odds of favourites doing so well assuming a 50% probability. If the faves had a 50% chance of winning each of the regular season's 256 games, then there was a 1.38% chance that faves would win 144 or more times. Unlikely, but not extrememly unlikely, and not too unlikely at all after 24 seasons.

The problem is that favourites don't really have a 50% chance of winning: in the 21 seasons from 1983 to 2003, faves only cracked the 50% mark three times, and even then maxed out at 53%. The average for faves over this period was 46.92%. If we assume these are the true odds of a favourite winning, then the chances of faves winning 144 or more games drops precipitously to 0.05%. There's a 98.80% chance that a 0.05% chance won't hit over 24 trials, as the 24 seasons since 1983 (the ones for which I have records) represents.

So now I'm a little uncomfortable chalking up the performance of faves in 2005 to statistical aberration. It's still possible, just very unlikely. So a question to those who know the NFL better than I do: did anything change in 2005, either on field or within the books? Does anyone know how professionals explained the performance of favourites last year? Because good luck might just not cut it.

Caveat: I'm not a statistician, though I think between Excel and my old A-level textbook that I've got this right. I'm certainly open to the possibility of correction though.

BobJoeJim · #6 08-29-2006, 05:31 PM

As much as I love to live and die by statistics, I think there's an interesting psychological way to look at this too; a classic example of how you can end up second guessing yourself.

Start with this hypothetical: There was an actual, systematic reason why the favorites covered so often last year. If true, do the books adjust? If so, then all bets are off (no pun intended) as to whether faves or dogs are a better pick this year. On the other hand if the books stubbornly stick to their guns, believing last year was just a statistical abberation, there may be a lot of money to be made hammering faves.

Now then, what if the books make an adjustment to correct, but last year in fact WAS due to random chance? Suddenly dogs look great! I could also see the books doing something like this to a lesser extent, to exploit the public if they think last year's trend meant something when it actually didn't. "Oh, you're going to bet all faves, regardless? Here, let's just make the line 7.5, not 6.5 then."

But on the other hand... go ahead, finish this sentence yourself, it's fun!

Okay, of course nothing I've said here is actually particularly useful, I don't think. It is a fun little thought experiment, though, if you like getting caught up in logic loops and paradoxes [img]/images/graemlins/wink.gif[/img]

flopking · #7 09-05-2006, 06:51 PM

assuming an efficient market hypothesis for the sportsbooks...

then I don't see how this could be anything but a anomaly

almostbusto · #8 09-05-2006, 06:53 PM

[ QUOTE ]
assuming an efficient market hypothesis for the sportsbooks...

then I don't see how this could be anything but a anomaly

[/ QUOTE ]so you are saying that if you assume this is an anomaly, then it follows that this must be an anomaly. brilliant!

EDIT: to add something worthwhile to thread perhaps. I doubt it was simply an anomally, though i don't have any more evidence than what has already been posted in this thread. either way though, i don't see the trend repeating itself this year.

Freerollin` · #9 09-05-2006, 06:57 PM

[ QUOTE ]
[ QUOTE ]
assuming an efficient market hypothesis for the sportsbooks...

then I don't see how this could be anything but a anomaly

[/ QUOTE ]so you are saying that if you assume this is an anomaly, then it follows that this must be an anomaly. brilliant!

[/ QUOTE ]

1. No, he isn't.
2. STFU

almostbusto · #10 09-05-2006, 07:04 PM

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
assuming an efficient market hypothesis for the sportsbooks...

then I don't see how this could be anything but a anomaly

[/ QUOTE ]so you are saying that if you assume this is an anomaly, then it follows that this must be an anomaly. brilliant!

[/ QUOTE ]

1. No, he isn't.
2. STFU

[/ QUOTE ]yes he is. EMH assumes that any error in pricing is 'a random walk' or whitenoise or whatever you want to call it. there was obviously a pattern last year, one that favored favorites. if you assume EMH to be true then this could only be the result of an anomaly since since all prices are efficient at all times + or - some epsilon whose value is centered at zero.

in this case there is strong evidence that epsilon is not zero centered, therefore the hypothesis is incorrect or there is an anomaly, there is no other option.