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Topic: Chance of winning and the betting line

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Cincydawg

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Chance of winning and the betting line
« on: April 06, 2018, 04:54:45 PM »
http://www.bettingtalk.com/win-probability-percentage-point-spread-nfl-nba/

This topic has always interested me, and the above is just one version of associating how often a favorite wins relative to the line.  For example, a 3 point favorite will win almost 60% of the time, which is pretty close to a coin flip.  At 7 points, it's 75%, and at 10 is 84%, and 14 is 92%.  We usually think of a 2 TD favorite as being almost prohibitive, akin to a game of Indiana playing at Ohio State, etc.  But the dog has an 8% chance of winning, and with as many games as are played each week, there is a good chance some 2 TD dog will win, and if it is a major game we notice.

This site goes to 100% at 17 points, which of course is not correct, but 20+ point favorites that win are major upsets, and we had Stanford beating USC a decade or so back as a 42 point dog.  That probably is a 1 in 10,000 shot.

If I think about this over the course of the season for a team like say Ohio State, presume they are favored in every game from 3 points in one game to 30 points in others, but also 7 points in a couple and 10 points in a couple.  It's not hard statistically to see a probable loss there somewhere, which is why undefeated teams are rare, even with a light schedule.

A way I try and calculate each team's likely end of year record is to take these percentages and multiply them out, chances of losing, which is a bit of guesswork, and see how many losses are "probable".  This usually generates more losses than one would think, or that really happen, over the year.  The above scenario for example cranks out 2.4 losses for Ohio State in this imaginary example.  I'm curious if anyone can spot an error in this methdology, aside from the guesswork's being wrong.

Cincydawg

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Re: Chance of winning and the betting line
« Reply #1 on: April 06, 2018, 04:57:23 PM »
https://www.beyondtheboxscore.com/2009/8/29/1003957/chance-of-a-football-team-winning

I like this link a bit better as it has graphics and more realistic odds I think.


847badgerfan

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Re: Chance of winning and the betting line
« Reply #2 on: April 06, 2018, 05:00:56 PM »
You'd be best served becoming an expert in roulette. I know I read that somewhere.
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betarhoalphadelta

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Re: Chance of winning and the betting line
« Reply #3 on: April 06, 2018, 05:29:23 PM »
You'd be best served becoming an expert in roulette. I know I read that somewhere.
I don't know about that... I think there's a legitimate ground for skill to give you an edge here.
Years ago, I spent an entire season publicly posting and tracking picks on my blog. Over the course of one season (2005 or 2006, can't remember which), I was picking 62.5% ATS, and all you need to beat the vig is 55%. I think college has much more variance (and probably a lot less attention) than picking NFL, and it's a lot easier to spot places where the line is just flat out wrong.
I did this through several ways:
  • I did not pick games involving Purdue or Notre Dame. Too much emotional bias.
  • I did not pick weeks 1 & 2 because it's too early to know what teams look like due to the degree of turnover on college rosters.
  • I primarily picked Big Ten games because those were the programs with which I had a high degree of familiarity.
  • Outside the Big Ten, I looked for games where I had a gut feel that the spread might be "wrong", and if my additional research backed up that claim, I included it in my spread tracking. 

Essentially what I found was that I'd be picking about 6-8 games per week. Assuming 8 games per week and betting $110 per game (to win $100, just using this for the math), I'd average winning 5 bets per week and losing 3. So I'd gain $500 per week vs a loss of $330, or $170 per week. Averaged over a season, I could've pulled down a good $1500 or so.

The follow-up question, of course, is "well then why don't you do it?"

To that I say this... It takes a lot of time and effort to put into those picks. At the time I didn't really want to devote $800 a week to a betting pool, knowing that a bad week could hit me hard. And all that work and research over a span of 3-4 months, for only $1500? It just wasn't a big enough win to justify the time and risk. If I'd actually wanted to make $1500 over that time, I probably could have found much less risky ways to do so.

To make enough money to be worth it also meant risking a lot more, and especially in 2005/2006 I didn't have a significantly higher bankroll (say betting $550 per game x 8 per week) to do it. 

That said, I'd bet that a lot of us on this site could pick games at a money-winning clip. Don't you think you could do better than a 55% record against the spread if you really put your mind to it?

847badgerfan

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Re: Chance of winning and the betting line
« Reply #4 on: April 06, 2018, 05:36:58 PM »
 :shut_up:
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Cincydawg

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Re: Chance of winning and the betting line
« Reply #5 on: April 06, 2018, 05:52:29 PM »
My post really is not about betting at all other than using the spread as an input variable.  It's more about the nature of upsets, and how "we" seem shocked at times when they happen.  We know they WILL happen of course, but not when, but this suggests that they become statistically likely if you have enough games of say 14 point dogs.


FearlessF

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Re: Chance of winning and the betting line
« Reply #6 on: April 06, 2018, 07:46:19 PM »
sh1t happens much more often if I have $$$ on the game
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MrNubbz

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Re: Chance of winning and the betting line
« Reply #7 on: April 06, 2018, 11:07:05 PM »
FF that seems eerily familiar.About 10 years back on a saturday I put $200 on 1 game and $50 on 3 others.I won the 3 - $50 bets and lost the $200 wager.Go 3 for 4 and lose coin,just seems to be the way it works.It's a real sad story
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ALA2262

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Re: Chance of winning and the betting line
« Reply #8 on: April 07, 2018, 12:13:04 AM »
I don't know about that... I think there's a legitimate ground for skill to give you an edge here.
Years ago, I spent an entire season publicly posting and tracking picks on my blog. Over the course of one season (2005 or 2006, can't remember which), I was picking 62.5% ATS, and all you need to beat the vig is 55%. I think college has much more variance (and probably a lot less attention) than picking NFL, and it's a lot easier to spot places where the line is just flat out wrong.
I did this through several ways:
  • I did not pick games involving Purdue or Notre Dame. Too much emotional bias.
  • I did not pick weeks 1 & 2 because it's too early to know what teams look like due to the degree of turnover on college rosters.
  • I primarily picked Big Ten games because those were the programs with which I had a high degree of familiarity.
  • Outside the Big Ten, I looked for games where I had a gut feel that the spread might be "wrong", and if my additional research backed up that claim, I included it in my spread tracking.

Essentially what I found was that I'd be picking about 6-8 games per week. Assuming 8 games per week and betting $110 per game (to win $100, just using this for the math), I'd average winning 5 bets per week and losing 3. So I'd gain $500 per week vs a loss of $330, or $170 per week. Averaged over a season, I could've pulled down a good $1500 or so.

The follow-up question, of course, is "well then why don't you do it?"

To that I say this... It takes a lot of time and effort to put into those picks. At the time I didn't really want to devote $800 a week to a betting pool, knowing that a bad week could hit me hard. And all that work and research over a span of 3-4 months, for only $1500? It just wasn't a big enough win to justify the time and risk. If I'd actually wanted to make $1500 over that time, I probably could have found much less risky ways to do so.

To make enough money to be worth it also meant risking a lot more, and especially in 2005/2006 I didn't have a significantly higher bankroll (say betting $550 per game x 8 per week) to do it.

That said, I'd bet that a lot of us on this site could pick games at a money-winning clip. Don't you think you could do better than a 55% record against the spread if you really put your mind to it?
Your point in regards to the first 2 weeks is the reason my brother spends the first 2-3 weeks of each season in Vegas. He contends the odds makers don't have a clue until the third or fourth week. 2010 was the first year he stayed more than 2 weeks. You mentioned ND, so I am sure you remember what occurred to them on that third week. My brother will never forget it. Just before the late game between ND and MSU started, he found himself holding a $250 seven game parlay ticket in which he had picked the first six games correctly and he had MSU as the winner of the seventh game. He still proudly carries the $500 losing ticket he placed as a hedge bet on ND. The Sports Book at the casino didn't have enough cash to pay off his $18,750 (75 to 1) winning parlay ticket. He had to take it to the main cashier in the casino.

MarqHusker

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Re: Chance of winning and the betting line
« Reply #9 on: April 07, 2018, 12:26:52 AM »
I agree.  My own history loves 1st couple weeks. Big arbitrage imo.  I never pick more than 3 games per week.  I get crushed in bowl games, and not so well in Nov.

Cincydawg

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Re: Chance of winning and the betting line
« Reply #10 on: April 07, 2018, 05:46:44 AM »
Bowl games also favor the dog I think in betting.  I also think you might beat the vig by betting against the NDs of the world.

Too many bet for their team to win, so find the team that has the most support and bet against them.

But my point is how often upsets happen.

FearlessF

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Re: Chance of winning and the betting line
« Reply #11 on: April 07, 2018, 09:49:01 AM »
Hah, you just keep trying to keep this thread on point with this crew

see how that works

heck, you know how this works
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Cincydawg

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Re: Chance of winning and the betting line
« Reply #12 on: April 07, 2018, 10:00:29 AM »
Which team has the prettiest cheerleaders? :57:

847badgerfan

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Re: Chance of winning and the betting line
« Reply #13 on: April 07, 2018, 10:04:13 AM »
Which team has the prettiest cheerleaders? :57:
You can win that way, like betting colors at the horse track.
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