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By analyzing the Wizard's data from 2013-2017 in his 'NBA betting' article, I noticed a huge discrepancy in some of the probabilities for certain spreads over that time period with a decent sample size of on average 350 games. The ACTUAL probability shows around a 5 to a 8.5% edge over the implied probability over this data set depending on which spread you choose in the chart. Now with that being said, this is comparing the edge vs a FAIR LINE, which is almost never the case when a bookie puts out a line, but that doesn't mean there still isnt value, supposedly at least. For example, looking at the +5.5 point spread(the spread with the biggest edge) from 2013 to 2017, in a 336 game data sample, the fair line or implied probability would be 29.3% or +241. The Timberwolves the other day vs the lakers was +5.5 and +200 on the moneyline with an implied probability of 33.3%. Although the bookies line is worse than the fair line price, the ACTUAL probability for this spread from 2013 to 2017 according to the Wizard's chart shows a probability of 37.8%, so still a 4.5% edge (37.7 - 33.3 = 4.5). You even had the Bucks at the Warriors the other day at +5.5 with a +220 line at a 31.3% implied probability and using the Wizards Chart again, we get a 37.8% probability for the +5.5 spread momeyline bet, which means there is about a 6.5% edge on that game and what do you know, the Bucks went into Oakland and not only WON but BLEW OUT the best team in the league, which is very interesting.

My problem with this is the following. After really thinking about it more and what Im really doing as a whole regarding collecting historical data in sports, I started to ask myself some questions regarding if this is even valuable information to make a sports bet truly +EV. Backtesting historical game information even IF it has shown to be +EV over a 350 game sample size or whatever size for that matter, doesnt mean ANYTHING. Each game is independent regardless of what happened in the past, especially for the data set I illustrated above when it is based off random teams as a whole. I mean if sports are truly random as everyone in the world including me throughout my life always believed to be true, how can this type of information or ANY backtesting information REGARDLESS of the sample size ever be helpful in the LONG RUN? Each game is independent just like the spin on a roulette wheel. It is impossible for anyone to predict a single game when there are so many moving parts each and every game such as players feeling sick without telling anybody, things going on in their lives behind the scenes, added motivation because a reporter or someone said something to them, or maybe just not in the mood that game, angry with teammates in the locker room, etc. Even if you dont use any backtesting information and just try to analyze each and every game, you still have no idea what will actually happen on that single night. The only reason bookies make money is because theyre ripping you off on the payout both on the moneyline and the spread with equal action on both sides. That has no subjectivity of it like trying to predict a game. They are guaranteed to make money as long as there is equal action on both sides.

If sports are truly not random and -EV, that would simply ruin sports for me as a whole, one of the things I enjoy the most. Because if it's not random, that would mean it's rigged or bias in some way that could make historical information relevant and that would make me lose all interest if I found out it's basically a programmed event regardless if I can profit from it.

Quote:ZK...I mean if sports are truly random as everyone in the world including me throughout my life always believed to be true, how can this type of information or ANY backtesting information REGARDLESS of the sample size ever be helpful in the LONG RUN? Each game is independent just like the spin on a roulette wheel. It is impossible for anyone to predict a single game when there are so many moving parts each and every game such as players feeling sick without telling anybody, things going on in their lives behind the scenes, added motivation because a reporter or someone said something to them, or maybe just not in the mood that game, angry with teammates in the locker room, etc...

To me, this looks like you're saying sports are random (50/50 chance) like a roulette wheel. Something that can't be predicted.

Quote:ZK...The only reason bookies make money is because theyre [sic] ripping you off on the payout both on the moneyline and the spread with equal action on both sides...

Are you saying because there's equal action on both sides the casino has an advantage? Or in other words, the odds they offer, in it of themselves, isn't +EV to the casino, but only as a whole?

How about this -- if you truly believe sports are random (50/50 outcome), you can book my bets. I'll lay -105 on whatever bet I want to make, and since they are 50/50, you'll have a 2.5% advantage. Okay, that offer was a bit facetious since I don't think you'd take it (but if you do, LMK), but would you bet some trashcan team at +105 odds vs the Warriors (or whoever's the best team)? If it's 50/50, you'd have a 2.5% edge. There are bets all the time that are greater than +105, why not bet anything and everything that's longer than +100 odds, because it's 50/50?

Sports are not 100% predictable, as in, for anyone to say with absolute certainty X team has a Y% chance to win or a Z% chance to cover. I think part of the problem is you may be viewing 'prediction' as something which is certain, when a prediction is really just that but with odds attached.

Quote:ZK...If sports are truly not random and -EV, that would simply ruin sports for me as a whole, one of the things I enjoy the most. Because if it's not random, that would mean it's rigged or bias in some way that could make historical information relevant and that would make me lose all interest if I found out it's basically a programmed event regardless if I can profit from it...

Sports aren't random because there's almost always going to be a favorite. That doesn't mean it's rigged or biased, at least not in the way I think you're thinking about it.

Over two dozen teams of almost seventy data analysts given one real world set from the year

2014 could not develop a valid response.

Just because the data shows certain bets in the past were +EV doesn't mean that can't change for one reason or another.

it's not debatable. it's just false.

the great majority of those who do beat sports don't do it by back testing a system although they may use that info

the great majority who do beat sports are able to do so because their opinion or insight has greater validity than that of the general betting public whose opinion is reflected in the lines and the odds

if for some reason they had to bet every game probably no one could beat sports

but they don't have to do that

they cherrypick

It is indeed hard to predict how much Alabama will beat Vanderbilt by, but there is nothing fundamental about either the money line or the sports spread that makes a wager a -EV proposition. Sometimes the bookies will set the line or spread so that it is not 50/50 because they make a mistake, there is something they are not aware of, they place too much weight on certain factors, they intentionally skew the bet because they are trying to balance the action and the public has an emotional favorite, etc.

And as others have said, it is important to understand that in some/most games the spread and/or line is set very well and it is a -EV proposition to bet on those games. You can only win by limiting your bets to those games where the line/spread is not 50/50 -just like you only double in BJ on those hands where the EV is positive and you Wong out when the EV is highly negative.

Your mistake is assuming "100% perfect efficiency in setting the line and spread."

Quote:ZenKinGNow with that being said, this is comparing the edge vs a FAIR LINE, which is almost never the case when a bookie puts out a line, but that doesn't mean there still isnt value, supposedly at least. For example, looking at the +5.5 point spread(the spread with the biggest edge) from 2013 to 2017, in a 336 game data sample, the fair line or implied probability would be 29.3% or +241. The Timberwolves the other day vs the lakers was +5.5 and +200 on the moneyline with an implied probability of 33.3%.

You can see that after I smooth out the ups and down, my probability of a 5.5-point underdog winning is 0.293188. So, if you bet them at +200, you would an EV of -12.04%. Negative indeed.

Betting the NBA

Backtesting data sets in sports is also completely flawed because its not comparing apples to apples and theres way too many moving parts happening during that sampling that can lead you to making false conclusions. NO ONE knows whats going inisde these players heads or the coaches heads, or who might get injured, or who might sit out a lot of minutes after slightly pulling a muscle because the playoffs are coming up, all of which can skew any data analysis or whatever you do to handicap the match for that single night.

So back to favorites and underdogs. Sure, people know that each game there is a bias of who might win, but you're getting ripped off on the payout and in the long run it's impossible to know how many times a certain favorite can really win over that type of underdog even if the historic data set probability you put together show it to be +EV vs the implied probability of the line put out by the bookies. The reason being is like I mentioned above, these historical probabilities are eadily skewed with too many moving parts during that period that give a false conclusion that a data set might be outperforming, but thats false. We then cluster these probabilities and think a bet is +EV, but dont realize what actually happened game to game for that data set to outperform.

Bookies at the end of the day just want equal action on both sides and is why the line gets adjusted up and down during the day when theres too much action on one side vs the other as im sure all of you know already. Bookies set the spread and moneyline based on public perception that will get the most even action as possible and if it doesnt work out, they adjust the lines up or down during the day to guarantee the vig/profit.

The only way to make money in sports is if you're a bookie or if it's rigged and you have inside information on one of the best players on the team or the refs throwing the game or other inside information that no one knows about such as someone who will only play half the game cause theyre sick or whatever. Thats completely different and comes down to inside information. With that information you can make a killing and also use implied probability to escalate your winnings even more. Im not debating any of that. Im debating the fact it's -EV for anyone who tries to 'handicap' a particular match. In the long run, youll lose out because no one knows the future long term probability of a single random event that changes game to game over time. Handicapping a match is not a linear progression. Sports arent linear. It is always changing and way too many moving parts game to game.

Quote:WizardYou can see that after I smooth out the ups and down, my probability of a 5.5-point underdog winning is 0.293188. So, if you bet them at +200, you would an EV of -12.04%. Negative indeed.

Betting the NBA

The 29.3% wasnt the actual probability that was gathered during the data set. The actual probability over time showed a 37.8% win rate for 5.5 point dogs. So at +200(33.3%), it was a 4.5% edge.

None of this even matters though because I dont believe in backtesting subgroups of data in sports anymore. The more I thought about it, it just doesnt make sense to me, especially when these subgroups of data clustered together had so many moving parts throughout the sample size. Most backtests done in sports is just a bunch of clustered data that wasnt apples to apples. One cant then just group it all together and say it's +EV. I think this is where many sports bettors get in trouble. Even single game analysis game to game is -EV because no one really knows what will happen 'exactly' on that day regardless of historic stats and matchups.

Sports arent linear or scientific. Nothing but an independent trial with illusions of data sub groups over time that can falsely lead someone to believe there is a 'trend' or a correlation of data going one way. Maybe player's mentalities were different before the game begun or maybe they had different motivations before the game, maybe someone got hurt, maybe they had a feud with the coach for the past week and it affected their performance and the teams performance, maybe someone had a lingering injury, way too many moving parts for backtesting data in sports to ever have any signifcant value in my opinion. Single game analysis, same thing, completely random game to game and just another indepedent trial.

Quote:ZenKinGEveryone is misunderstanding me once again. It has nothing to do with the bookies because theyre irrelevant in this conversation, theyre just like us in knowing what will happen in the long run, except they have the advantage of getting to make money by having a 'guarantee' with the vig and having equal action on both sides.

First misconception: there is no possible way for any book to "guarantee" two way betting so that they have a profit before the game even starts. The casino loses money on nearly half of all spins of the roulette wheel or hands of blackjack. And a sports book loses money on most of lines they put up.

Quote:ZenKinGI dont care about what the line says. My OP had nothing to do with the 'certainty' of lines or any of that. My point is it's IMPOSSIBLE to know what the outcome of an indepedent game will be each and every night assuming the refs and players are honest and the game is played fairly both ways.

No one who makes money off this (whether a bettor or a bookie) is looking for any sort of certainty. They're looking for probabilities. It's almost exactly the same as a hand of blackjack. (and it's surprising someone who earns a living off such small changes in probabilities would take this position). Take a look at these early season college basketball totals. There was 148.5 and 151.5 on the Florida State game yesterday available at the same time. Because there is a non-zero probability that final total lands on 149, 150, or 151, one (or both) of those sides must be +EV. Even easier to find this in first half totals. There are examples of this nearly every day. Expected Value has absolutely nothing to do with certainty.

Quote:ZenKinGThe only way to make money in sports is if it's rigged and you have inside information on one of the best players on the team or the refs throwing the game or other inside information that no one knows about such as someone who will only play half the game cause theyre sick or whatever.

Now you're contradicting yourself. You say the sports books make money by shorting payoffs; now you say the only way to make money is by inside information. Which one is it?

Quote:ZenKinGIn the long run, youll lose out because no one knows the future probability of a single random event that changes game to game over time.

Consider a sports book with a line at -140 and +120. The one thing I know for sure is that the probability cannot be both 58.33% and 54.54%. It's likely somewhere in the middle. So when I see +145 I'm going to take a position and bet one or those

Quote:ZenKinGIm debating the fact it's -EV for anyone who tries to 'handicap' a particular match.

But the sports books do this all the time and 'handicap' (or shade) the probabilities against how their customers have bet in the past. It's why there was Mississippi state available at +24.5 some places on Friday when other places had Alabama -22. The sports books didn't know the exact probabilities, but some of them knew their customers were more likely to bet the favorite, so they inflated the line. And with a non-zero chance of the game being decided by exactly 24 points, that's exactly what happened. It doesn't take a lot of these results to turn a losing bettor into a winning bettor.

If you're claiming that the lines cannot be beat, than that is saying that all you have to do is beat the (closing) lines and it is +EV

-----

This is just the easiest way to see +EV opportunities. The most obvious other one is correlated parlays. There is also simply having a better model than the sports books. Like you say, there is nothing special about what the sports books are doing, so when teams of the brightest minds work together, they have been able to come up with ways to do it -- and have the tax returns to prove it. For those of us on the bottom levels, the smallest, slowest moving markets are often the best. Consider the run in the first inning prop in baseball: It's such a small market that the opening line isn't going to change until someone bets it, even when the total drops because of weather or a change in the starting lineup -- so I'll be the one to bet it.

If the spread is Jets favored by 42points, then you have a +EV bet on Saints +42.

If the spread is Saints favored by 150 points, then you have a +EV bet on Jets +150.

In between those two absurd extremes, is the full spectrum of probability. It depends on the spread or line that is set by the bookies as to whether you have a +EV or -EV bet. Most of the lines on most of the games will be -EV but inevitably some will be +EV.

Quote:ZenKinG

The only way to make money in sports is if you're a bookie or if it's rigged and you have inside information on one of the best players on the team or the refs throwing the game or other inside information that no one knows about such as someone who will only play half the game cause theyre sick or whatever. Thats completely different and comes down to inside information.

the only important question brought up in ZK's posts here is why he puts out obviously false statements such as this.

this is like the guy who loses 17 out of 20 even money bets at a roulette table and goes around screaming that the wheel is rigged

Quote:ZenKinGNot going to keep repeating myself. People need to see what Im even talking about to understand where Im coming from. We're talking about 2 different things.

The fact that you think any bookies have even action on both sides of a game is the first problem

Quote:ZenKinGNot going to keep repeating myself. People need to see what Im even talking about to understand where Im coming from. We're talking about 2 different things.

You're talking about sports bets being -EV at all times with the only exceptions being bookies and inside information. Everyone else is talking about why that isn't true.

If that isn't correct, instead of repeating yourself, how about clarifying it?

Quote:michael99000The fact that you think any bookies have even action on both sides of a game is the first problem

Never said that, but nice try. I said they try their best throughout the day to get it to 50/50 on both sides to collect their preset juice/vig.

Also to the ones saying I dont understand probability, not sure why you would say that unless you didnt read my original post. I understand implied probability and the difference between certainty, probability, and expectation. I was never debating implied probability of a certain line. Im debating the ACTUAL probability in sports that it cant be determined scientifically in the long run because its a random event with too many moving parts. I even gave an example of a data set from the Wizard's NBA betting article where I found a 350 or whatever size data sample for +5.5 dogs where the ACTUAL probability was over 8% higher than the fair line / implied probability, but that was against a fair line and no vig so then I gave another real world example with a line from the timberwolves game at +200 at 33.3% and because the ACTUAL probability from the data set was around 37.9% for 5.5 point dogs, you had around a 4.5% edge on that bet, but as I thought about it more, thats assuming ACTUAL probability in the long run has any significance when it comes to sports and it doesnt. Sports cant be simmed. Theres nothing scientific about it. Its a completely random event with favorites and underdogs, but nonetheless still random when trying to compute long term probability.

My point was about the ACTUAL probability not IMPLIED and how no one will ever know the long run probability of a random single isolated event in sports to use any of that backtesting information or whatever to their advantage. I dont care about how many times I need this line bet to win to breakeven. The point is NO ONE knows the ACTUAL long term probability of breaking even so knowing the implied probability is irrelevant.

a lot easier than admitting that people are better than you at it

he read a few paragraphs on a sports betting website and now 𝐇𝐄 𝐊𝐍𝐎𝐖𝐒 that no one can beat sports

Quote:lilredroosteranyone want to make odds that ZK just lost a bunch of sports bets so he decided that if he can't beat sports nobody can?

a lot easier than admitting that people are better than you at it

I havent bet sports in many years so nice try and when I did, it was recreational and low stakes at first betting without any real data analysis on the NBA, which I know a ton about, where I lost a small amount and then I tried again after backtesting a lot of data to see if I actually had an edge, and ended up breaking even or again lost a very small amount. I then just stopped and focused on a more precise edge with blackjack after I had a manageable bankroll. I recently thought about betting again thinking that backtesting data can result in an edge by using the charts from the Wizard's NBA betting article until it finally clicked that backtesting data in sports is all B.S as well as single game analysis and there really is no edge so ill never bet again.

Last thing I would do is come to vegas and risk any part of my bankroll when I now have expenses without fully knowing I have an edge. You'll probably never run into a more disciplined AP at least with the way i play and manage my risk. My only flaw is that I have anger bursts, but Im proud to say I never have let it affect with how I actually play. I never overbet or steam chase a loss or get into any other areas of AP unless I can convince myself I have a mathematical edge. I consistently keep my risk below 0.5% or lower and resize constantly if a losing streak happens. Proof of my discipline is you'll be hard pressed to find another counter who can purely backcount and go casino to casino without placing a single bet for hours on end. I might be the only one alive doing that. Every other counter plays off the top and wongs out or plays all.

Quote:ZenKinGIm debating the ACTUAL probability in sports that it cant be determined scientifically in the long run because its a random event with too many moving parts.

But it doesn't have to be determined "scientifically." It could be determined subjectively, experimentally, logically, or through many types of methods.

With a 5.5 spread in an NBA game, that means the estimated probability should have the favorite winning by 6 or more about 50% of the time, with the underdog covering about 50% of the time. That also means if a bettor can get the underdog at +6.5, the estimated chance of winning should be 50% + the probability the favorite wins be exactly 6 -- which must be more than 50%. Sometimes it will be enough to turn a -EV bet into +EV.

Quote:TomGBut it doesn't have to be determined "scientifically." It could be determined subjectively, experimentally, logically, or through many types of methods.

With a 5.5 spread in an NBA game, that means the estimated probability should have the favorite winning by 6 or more about 50% of the time, with the underdog covering about 50% of the time. That also means if a bettor can get the underdog at +6.5, the estimated chance of winning should be 50% + the probability the favorite wins be exactly 6 -- which must be more than 50%. Sometimes it will be enough to turn a -EV bet into +EV.

Too many assumptions for my liking. Too many 'shoulds' and too many 'estimates'. To each their own.

Quote:ZenKinGThe 29.3% wasnt the actual probability that was gathered during the data set. The actual probability over time showed a 37.8% win rate for 5.5 point dogs. So at +200(33.3%), it was a 4.5% edge.

I had only 336 games in the data with a 5.5-point favorite. The standard deviation on a sample that small is quite big. That is why statisticians smooth out all the data to look for trends.

Regarding your other points, I would agree, but probably not for the same reasons, that handicapping the major sports is not positive EV, unless you have inside information or have a Billy Walters level of skill at it. I have met quite a few people who called themselves professional gamblers at handicapping, but none of them withstood the test of time. A couple of them became touts, which is a "profession" I don't have much respect for.

I do think it is possible to be an AP at sports with no handicapping skill at all. The half-point parlay cards are a good example. You have to exploit the odd-ball stuff.

Quote:ZenKinGToo many assumptions for my liking. Too many 'shoulds' and too many 'estimates'. To each their own.

Would you say that any occupation (like a doctor or lawyer) other than counting cards must be -EV simply because it doesn't fit your liking? Bezos and Buffet had to make market estimates to earn their money instead of relying on "scientific" formulas. The paths they have taken to earning income couldn't be tracked by a simulation either.

I don’t completely agree nor completely disagree that you can’t get an edge from backtesting. It’d really depend on the data and type of bets and what you’re going after, IMO. Obviously certain things are going to be stronger than others. If you cherry pick data and find some anomoly, like “+200 or longer dogs that have been on the road for 2 weeks after losing 50%+ games by double digits” is probably useless info, while looking at something like the odds that a 5.5 pt dog wins is X% is going to be stronger, in my mind at least.

But I, nor anyone I know, bets sports based on backtested data.

Quote:TomGWould you say that any occupation (like a doctor or lawyer) other than counting cards must be -EV simply because it doesn't fit your liking? Bezos and Buffet had to make market estimates to earn their money instead of relying on "scientific" formulas. The paths they have taken to earning income couldn't be tracked by a simulation either.

The casinos are filled with these types of people at the tables. They're called 'system players'. Casinos rely heavily on that type of mindset.

Using Bezos and Buffett is a completely different subject. Buffett invests widely in long term stable net positive high earning types of companies. Thats not exactly -EV or a non scientific method of achieving wealth. Im actually very fond and will eventually adopt his investing strategy. He believes very heavily in index funds and slow long term wealth building. He believes in it so much, he wants 95% of his wealth to be left for his wife in the form of index funds. I probably woukdnt do 95%, as I would like a portion invested in hard assets such as gold and silver and maybe a bit in real estate, buf for the most part I agree with his whole investi g mindset. Wealth is not a race, slow long term investing is the key.

Maybe you shouldve used day traders and swing traders in your example and left Buffett out of it. Thats a bit more keen to the subjective non scientific mindset.

Quote:TomGBut it doesn't have to be determined "scientifically." It could be determined subjectively, experimentally, logically, or through many types of methods.

An hour extreme case was the Floyd/Connor fight.

Anybody who understood the situation made Floyd a 98% favorite or higher.

Was it within the realm of possibility that Floyd would throw the fight for some reason, or try to fight with a terrible illness or that Connor actually was the greatest athlete of the past 1000 years? Maybe he could also win The Masters?

Sure. But you are making the best estimate based on the information available.

It's something like calling a bluff in poker. It might be that villain literally never bluffs. So the chance of them bluffing is zero. However, you probably don't know that. You have to make an educated guess and just come up with a probability. Some people are very good at that.

I do agree with the wiz that, in most cases, handicapping is so difficult you shouldn't worry about it. It also takes a lot of time.

Quote:lilredroosterif what you are saying is that nobody can beat sports in the long run that is false

it's not debatable. it's just false.

I'm not saying that. Just like a blanket statement of "Blackjack is -EV" is true, that's not the case for the few that can card count. For the 99.999999% of the players, it is -EV, just like sports betting.

100% agree. That is why this business is thriving. And that is why I put $5 at a time. Just for fun.Quote:SM777I'm not saying that. Just like a blanket statement of "Blackjack is -EV" is true, that's not the case for the few that can card count. For the 99.999999% of the players, it is -EV, just like sports betting.

I remember Zenking saying somethin about the Bulls so wish me luck, watch me win

EDIT: also Mavs +0.5 1st half. Bulls must be really poopy

Quote:speedycrap100% agree. That is why this business is thriving. And that is why I put $5 at a time. Just for fun.

NBA betting industry is extremely profitable, especially online betting sites related to sports. I think the reason is obvious WHY.