The MLB data covers 16 seasons (including the current one), which is 38,171 games, and never has there been a Total higher than 14.5 runs.
Until today.
Unless there's an adjustment, the London Series game between the 'home' Boston Red Sox and visiting New York Yankees had the Total set at 15, not high enough to prevent Overs from another comfortable win.
The previous high of 14.5 runs was set in April 2010, for a day game at Wrigley Field, and again the outcome was Overs as the Chicago Cubs beat the Arizona Diamondbacks 13-5.
Since 2007, there have only been 12 matches with a Total higher than 12.5, and 9 have gone Over. Those public biases helping the informed bettor perhaps, although it's a small sample.
Incidentally, today is the first time ever that two such games have been played on the same day.
The higher totals tend to be set in National League ballparks of course, and all-time the record in these games (Total 13+) is 36-27-7, which at Pinnacle's -105 works out to an ROI of 10.4%.
In matches where the two teams scored 13 or more between them in the previous game, the ROI is 26.2% suggesting that when the batters are hot, they stay hot.
Sunday, 30 June 2019
London High
Saturday, 29 June 2019
Football Unders and London Overs
The average overround was 105.4%, and Over 2.5 was the result in 805 matches (53%).
In matches where the teams 'true' win probabilities were within 25% of each other, the average goals per game was 2.56, while in more one-sided games, the average was 2.79.
Backing the Under 2.5 goals in these 279 matches would have resulted in a loss of 16.01 points (ROI -5.74%), which is pretty much the overround, and where the threshold is 10%, the 109 matches resulted in a small profit of 2.95 points. These games averaged just 2.51 goals per game.
Switching sports for a moment, and I'll update June's numbers after the weekend, but the visit to London for MLB offered a great value bet on Overs.
London Stadium is smaller than your typical MLB ballpark. It’s only 385 to dead center field and 330 down the line to either foul pole. The distance to “deep” center is shorter than any current MLB ballpark and well below the league average of 402.6 feet.
Monday, 24 June 2019
17 Leagues, One Season, One Result
As was the case from 2012-2018, overall we again see the expected improvement as the matches become more competitive.
Coming in to this season, the evidence indicated staying away from the smaller leagues of Belgium, Netherlands, Portugal and Scotland, as well as England's League One.
How did these leagues fare last season? More of the same essentially.
Prior to this season, the profitable leagues were the top two tiers of the Big Five countries, and again backing the Draw in all competitive matches in these 10 leagues was profitable:
As most readers will know, this season saw a record low strike rate for Draws in the English Premier League, the fewest since 1931-32 which most readers won't remember.
Even with the EPL's 14.43 point loss at the 'Difference less than .25' level, the overall return of 3.2% for the 'Top 10' was the same as for 2012-18.
For serious bettors, the biggest concern should be the increase in over-round last season. It's a topic covered previously in the blog, but every one of the 17 leagues saw an increase this season, with the EPL at an average of 103.5%. That may not seem like a lot, but it makes a huge difference over time and it's a worrying trend.
The full seven season summary looks like this:
In 2017, I referenced David Sumpter's conclusion, based on five EPL seasons 2011-2016, that:
It turns out that when two well-matched teams meet (i.e. the probability of a home win is only slightly bigger than the probability of away win) then draws are under-priced.The seven seasons for which we have reliable data show that this continues to be true in the big leagues, but not in the fringe leagues.
Just as I thought I was done, and could enjoy the summer, Joe threw another idea out there:
Looking at the average prices for the Over / Under for the EPL from last season, we're looking at an over-round of 105.2% which might be a problem. That there is a correlation between Unders and Draws will not be a surprise to readers of this blog but it might be an interesting exercise to look at some more data.
Saturday, 22 June 2019
17 Leagues, 6 Seasons, One Result
The 17 leagues are comprised of the top two tiers of the Big Five leagues (England, France, Germany, Italy and Spain), plus Leagues One, Two and National in England, and the top leagues in Belgium, Netherlands, Portugal and Scotland.
Not surprisingly, each league has its idiosyncrasies, not to mention varying over-rounds, and Joe followed up with:
Before I get to last season, here are the numbers for the seasons for which we have Pinnacle's Closing Prices which are available at Joseph Buchdahl's Football-Data.co.uk site.
Some additional clarifications are that:
- The seasons covered are the six seasons from 2012-13 to 2017-18
- All Profit and Loss calculations use Pinnacle's Closing Prices
- Any matches where Closing prices are missing have been excluded
- 'Competitive' is defined as matches where no team has a 'true' win probability greater than 0.5
- 'True' means after the over-round has been removed, i.e. the sum of the probabilities equals one. They are not truly true, but they are close.
There are faster ways of losing money than backing the Draw, but we can do better.
The next block shows the outcome of backing the Draw only in competitive matches, and the loss in this category is 1.4%.
Then I looked at matches where the two teams are within 25% of each other in terms of win probability, and finally at the relatively exclusive category where teams are within 10% of each other.
To keep Joe somewhat happy, 2018-19 is still to come, here are the numbers for Belgium and Netherlands:
As Joe suspected, these leagues do not follow the overall pattern, in fact the Netherlands results are the exact opposite of the overall results. Just back the Draw when a team is odds-on, and count the money, except that the market seems to have corrected since 2015, so this strategy is not recommended.
The only other league which is upside down like this is League One, although here we go from bad to worst with poor results across the board.
The other English leagues all follow the expected pattern, with the Premier League noticeably strong, something that will come as no surprise to readers of this blog.
For the Big Five leagues, the results for the top two levels are:
I'll update these results with 2018-19 in the next few days.
Meanwhile, if anyone is interested in detailed results from any of the other leagues, let me know.
Tuesday, 18 June 2019
A Tale of Two Podcasts
I was thinking in the shower this morning, (yes, once a week, whether I need one or not), Betfair really is the ultimate video game. I've never been one for games, (friends at work spend hours playing Call of Duty - why? What's the point?), but in many ways the exchanges are one big on-line game. It's me versus an unknown opponent. My opinion versus yours, except in this game the points are real money.Or as Warren Buffett describes beating the markets:
"In a sense, the game that I'm in gets more interesting all the time. It's a competitive game, it's a big game, and I enjoy the game a lot"It's not often that I can compare myself with Warren Buffett.
There's plenty of other content that is worth listening to, if only to understand the level of competition you are up against if you are trying to create a model, and how the markets have changed over the years, although Rufus is a relative youngster!
He also claims at the end to not be a speaker, and hopes people will make it through the podcast, but for me it was easy.
This was a very good listen.
Mel is most definitely not a speaker, but appears to be blissfully unaware of this, offering viewers / listeners a 100 minute mono-tonal lecture, littered throughout with "you knows", or at least the parts I selected at random were, and remarkably absolutely no content of interest. I take my hat off to anyone who can sit through this, and if there is anything of interest, please let me know along with the time.
One unintentionally amusing moment I did stumble upon is when Mel explains how he had a problem registering with bet brokers who don't accept UK customers, but then suddenly realised he had dual citizenship. Problem solved!
Amazing stuff. I mean, who among us hasn't suddenly remembered that we have dual citizenship when it comes to betting? While it is true that this is a useful advantage, it's not likely true that its value only dawns on a bettor several years into his betting adventure. As a plot twist, this one is a little bit of a stretch.
I shall leave to the reader to draw their own conclusions as to why the loss of such a small amount, a miniscule draw-down from the profits already (supposedly) reaped, would trigger a ten week disappearance, and the need to "Reflect, Recover and Restart", but to be clear, the idea that anyone can consistently have a win rate of 55% to 60% for an outcome with a probability of .357 (i.e. 2.8 in decimal odds) is complete and utter nonsense.
Some markets might be inefficient, but none are quite that inefficient, or would remain so for long, and as I have written before:
This risk to reward ratio implies an average price of 2.8, i.e. a win probability of 35.7% for his bets, so anyone achieving a 50-60% win rate at that price would clearly, and rapidly, be on the way to a fortune and keeping very quiet about it.
If, by some miracle, Mel really does reside in a world where the laws of probability actually suspend themselves [say Hi to Tony while you're there], the idea that the amount risked should be 1.5% is similarly, literally incredible.
Using Kelly, the suggested stake with this kind of an edge is over 28%, which should be a clue that something doesn't quite add up!
Even a more modest quarter-Kelly suggests a stake in excess of 7%, so either Mel is terribly confused about the edge he has or he's clueless about how to make the most from it.
The evidence suggests that both are true.
I did attempt to listen to a few minutes to see if Mel had learned anything, but once the name of fantasist Adam Heathcote was mentioned as a source of inspiration, it confirmed that thinking logically is still not Mel's strong suit.
Not a good listen - unless you have trouble sleeping.
"You can't speak butterfly language to a caterpillar." - Unknown
Sunday, 16 June 2019
Flipping Variables
I mentioned recently the importance of having a logical reason why a system should work, rather than using 'data mining' to find a back-fitted system which has no predictive value at all.
For example, yesterday's post shared an idea for a system which takes advantage of the idea that the issue of time zones in the NBA may not be fully understood by the public, and as hopefully everyone understands by now, these situations offer an opportunity, at least in the short-term.
Contrast the solid logic and rationale of this idea with my tongue in cheek example of:
Back the Home Favourite in an American League game when the pitcher lost last time out, the visiting team won their last game but gave up two runs or more in the third, the temperature was 73F or hotter, and the game is being played on a Thursday afternoon.One of the forums I frequent regularly has such 'systems' recommended by contributors, but sadly most have them have multiple conditions applied. For most of these, there is simply no logic or rationale as to why this condition might lead to a market inefficiency. Fortunately, there is the occasional nugget that does makes sense, but these tend to be rare.
There was a voice of reason who jumped in on one 'idea' as it spiraled out of control, and explained the problem quite neatly, and while I have taken the liberty of correcting errors of spelling, punctuation and grammar to improve readability, the gist of the comment remains valid.
I need to speak out in terms of experience here before someone gets hurt.
The system included here has little likelihood of future success, and here is why. My experience, which is plenty, has shown me that when you back-fit a situation with so many conditions (at least 12 here), you're no longer predictive in terms of the future, but creating the most perfect flow chart of the past.
Most of these systems are built on finding something with a modest ROI, and then experimenting with variables, meaningful, or meaningless, adding only those that make the situation appear better.
If you experiment with a lot of variables, then you will "stumble" into those that make a certain situation look better, but in the process, you "contaminate" future predictability.
What you are left with is thinking and believing you have found the holy grail of sports betting, only to be fooled by a false premise of profitability. I guarantee you over the next 100 games, the win rate will be closer to a 0% ROI than to the back-fitted ROI.
We are putting faith in a system that is built upon 12-15 conditions, many of which are used, not out of known predictive advantages, but out of anything that improves the win rate. By definition you will find something that is better than the one condition variable.
Think of this. You flipped a coin 200 times, and without adding any filters your results were 100 heads and 100 tails, no predictability of future flips.
You video taped every flip. Now you go back and analyse what happened. You notice that when you flipped with your left hand, heads came up 55 times out of 100, while when you flipped with your right hand, heads came up just 45.
So you add the variable, if flipped with left hand, 55% of the time you get heads!
Further looks see that if you placed the coin in your left hand from your right hand you got 30 heads and 20 tails, but when you picked the coin up instead without any use of your right hand, you got 25 heads and 25 tails. So you're now up to a way to get 60% heads!
Next, you noticed if you paused for more than 10 seconds after placing the coin in your left hand from your right, you got 17 heads and just 8 tails. You now have a situation that generates 68% heads, just by flipping the coin from your left hand after placing it there from your right hand, and waiting at least 10 seconds before you flipped it.
So my question is:
If you then flipped the coin 300 more times, doing everything the way you did to get 68%, what percentage of heads is expected from the 300 flips?
The answer is 50%!
The variables used above were selected not based on anything that is predictive, but based on anything that made the system look better!
THAT IS THE PROBLEM!
The heads scenario here was built the same way, none of the added conditions are predictive in any way!
The moral of the story is this:
Build a concept on known +EV variables, not a system built to make +EV concepts.
What do I mean by meaningful variables? When you do a search in a given sport with one variable, and it shows an advantage, then you have found a meaningful variable.
Build a pile of meaningful variables for a given sport, then stack the meaningful variables, to get meaningful situations.
Hope that helps everyone here.I should add that it is quite possible to identify a variable that appears meaningless but for which it later turns out there was a valid reason all along. A Tweet from A Lucky A Day referenced the 15th a few weeks ago.
In a sumo tournament, all wrestlers in the top division compete in 15 matches and face demotion if they do not win at least eight of them.
The sumo community is very close-knit, and the wrestlers at the top levels tend to know each other well. The authors looked at the final match, and considered the case of a wrestler with seven wins, seven losses, and one fight to go, fighting against an 8–6 wrestler.
Statistically, the 7–7 wrestler should have a slightly below even chance, since the 8–6 wrestler is slightly better. However, the 7–7 wrestler actually wins around 80% of the time. Levitt uses this statistic and other data gleaned from sumo wrestling matches, along with the effect that allegations of corruption have on match results, to conclude that those who already have 8 wins collude with those who are 7–7 and let them win, since they have already secured their position for the following tournament.
Saturday, 15 June 2019
Fast and Three
So in the space of two days, both the NHL and NBA seasons are over, and it's all about baseball for the summer.
At the start of the 2017-18 NBA season, I shared some thoughts regarding the totals markets that even the most critical of readers would struggle to find fault with.
Actually, the only fault was that I underestimated how rapidly the totals would increase, and the suggested entry point of 215.5 soon became unmanageable, although had you been on all of them, you'd have been rewarded, but 431 bets over six months is a lot of work.
Whatever your entry point, the key to this idea is that the public have been slow to adjust to changes in the game, and the resulting higher totals.
It’s just one more home court advantage for West Coast teams, hosting sleepy teams from the East.One problem with defining teams as Eastern or Western is that a match between teams from the two conferences isn't necessarily a match between teams from different time zones, with the Central Time Zone having both 'Eastern' and 'Western' teams. The Eastern Conference spans two time zones, while the Western Conference spans three.
So an Eastern (Central Time Zone) team playing at a Western (Central Time Zone) is at far less a disadvantage than an Eastern (Eastern Time Zone) team playing at a Western (Pacific Time Zone) team.
After reading that article, I made some adjustments to the "Tired NBA Eastern Road 'Dogs in the West" system, excluding matches between teams in the same time zones for example, but the research uncovered a fact that was even more interesting. Games involving teams traveling west don't have as many points scored as the market expects. In a league where the talk is all about the increase in scoring, finding an edge on Unders was promising to say the least.
Here are the results from backing the Under when Eastern Time Zone teams headed west for a game in a different time zone for the past ten seasons:
As the prior would suggest, the edge is stronger in the Pacific time zone than in the Central, with the Mountain zone hosting relatively few games.
Using Joseph Buchdahl's spreadsheet, the chance that the results in the Pacific time zone are luck is 1 in 106. I share this idea because I'm a generous chap, and by the time the 2019-20 season rolls around, you'll all have forgotten about it!
And for what it's worth, I use the previous season's average points total (adjusted) as my entry point because not all Unders are value.
Thursday, 13 June 2019
Take The Money Or Run?
In baseball betting, the question of whether it is better to bet on the Run Line or the Money Line is often asked, including on my Twitter timeline yesterday.
It shouldn't be a surprise that road (away) teams win a higher percentage of games on the Run Line than home teams, because if the home team takes a lead in the bottom of the ninth or an extra inning, the game is over.
The road team doesn't have the luxury of knowing what is required, and so they will keep trying to pad any lead.
The statistics show this quite clearly - from a robust sample size of 37,905 matches, the percentage of wins for road teams covering the Run Line is 75.4%, while for home teams, it is only 68.1%.
But of course, the market knows this, and the Run Line price is derived not only from the Money Line price, but also from the venue.
The table below shows the approximate Run Line prices for some of the more common Money Lines, broken down by Home and Away and by league.
The evens Run Line bet for a Home team falls around the PW = 0.675 mark, while for the Away team, it's around 0.62.
But this chart is an average guide for MLB overall. The sharper minds among you are probably asking yourselves, "but isn't there a difference between the numbers for the two leagues?" and you would be correct. The Designated Hitter rule applied to games in American League ballparks, of course influences those numbers.
For example, the Run Line price on a -200 Money Line favourite (1.5) will average 2.087 if it is a National League team playing at home, to 1.8 if it is an American League team playing away.
Then of course you need to look at whether they are playing away in a National League ballpark or an American League one. Averages only take you so far.
One of the baseball ideas I've shared in this blog is the T-Bone system, and the results for Money Line and Run Line from 2011 to yesterday are:
Note that these profits are calculated based on risking the line to win one unit when playing on favorites, and risking one unit to win the line when playing on dogs.
Looking at 'hotties', which have been a value bet since 2014, for home teams the ML ROI is 5.2%, while the RL 6.0%, but on the road, the percentages are both 9.9%.
The public tends to favour home teams and be nervous of hot favourites in baseball, and other sports too, so the results aren't a huge surprise. That the inefficiency persists for so long, is.
Oh My Yosh!
Although I pretty much ignore the murky world of tipsters, this story of Darren Rovell appeared on my timeline and might be of interest to some of you familiar with the Action Network.
Darren Rovell, the former ESPN sports business reporter who currently works for the Action Network, a subscriber-based sports gambling information website, found himself under intense scrutiny after gambling aficionados on Twitter posted evidence he’d edited his bets after they’d been placed. And those bets were originally larger by many orders of magnitude than his usual bet sizes.The importance of measuring the success of a tipster or system against level stakes is highlighted, in particular by the use of "yoshing", a term I hadn't heard before, although the strategy wasn't new.
Why would a gambler place bets like these? According to one bettor knowledgeable about sports wagering who agreed to speak with me on the condition of anonymity, the practice of suddenly and randomly increasing bet sizing by several orders is commonly referred to as “yoshing.”
When a sports tout is facing a losing record at the end of a sports season, there’s not much downside in placing wild bets that, if they pay out, give the appearance of a positive year overall.
“If you win, great, you can claim you finished the season a winner,” the bettor said. “If you lose, who cares? You were already in the red.”
As noted above, Rovell denied he was yoshing at the end of the college basketball season, but rather blamed the error on his unfamiliarity with certain aspects of gambling.To be taken seriously, anyone claiming success needs their results to be verifiable. This is easy enough for pre-off bets, since there are published Closing Odds or sports databases available, but it's a challenge for those who make claims about being profitable on in-play betting.
Aside from the time needed for the latter, there's no guarantee that money will be available at a value price (if you're using the exchange) or that the bet will be accepted (if using a sportsbook).
If you can make money betting in-play, then good for you, but because it is essentially anecdotal, and unverifiable, it's really not something worth sharing.
Puck Review 2018-19
Another market inefficiency paid dividends last night with the conclusion of the 2019-19 NHL season, and the Stanley Cup being won for the first time by the St Louis Blues.
When a series goes to a Game 7, the public bias is to favour the home team, and with the higher profile of the game, they appear to back up this bias with money, which leads to an opportunity as A Lucky A Day stated back in January of 2018:
The NHL re-organised in 2013, and since then there have been 42 game 7s. Admittedly not a huge number, but the road team has won 22 of those games at an average price of 2.284 for a 17.9% ROI.
Over the same time period, the ROI for this strategy in the NBA is 8.4%, while in the MLB it is 29%, which sounds great, but the playoffs there are a different format, and there have only been eight game 7s.
Looking back to the 2004 season, which is as far back as the database goes, the ROI is 9.7% from the 17 matches.
We could have another Game 7 in the NBA if the Golden State Warriors win their last ever game at Oracle Arena tonight.
Back to Ice Hockey and while the NHL Regular Season was excellent, the post-season playoffs were terrible.
The above basic system was mentioned in October, in a post that looked at the claim that early season favourites were undervalued. I didn't find any evidence of this with the favourites my system uses.
Skeptics won't be budged, but the evidence to me is clear that the market is inefficient in these games. If you'd started backing these selections in 2016 after seeing the previous three seasons show great promise, the statistics for the past three seasons are:
If you're a risk taker and had taken the plunge after two seasons the 1-in-x probability becomes 1336:
This is a system I'll be playing again next season.
Tuesday, 11 June 2019
Segunda Finishes Second
Spain's Segunda División wrapped up at the weekend, finishing as mentioned previously, just behind Serie B, at least in terms of the Draw strike rate.
As with Serie B, this league is another one where the Draw is perennially a relatively big hitter. For the past six seasons, the strike rates are: For comparison, the EPL has not had a season in that range since 2010-11. Like its Serie B cousin, this league also has few matches where the Draw is at 4.0 or higher, fewer than 7% last season.The Draw was priced as favourite, or joint favourite in 16 matches, even more than Serie B's 10 matches, and was priced at 3.0 or shorter in 115 matches. ore evidence if needed, that this is a different world to the EPL, where in 7,220 matches, the Draw has never been favourite.
Backing the Draw in 'close' matches had an ROI of 6.64%, and as with Serie B, the return in these matches where the home team is favoured is higher than when the away side is favoured.
Serie B and the Segunda División were the only two leagues of the 17 I follow where the Draw occurred in 30% or more matches.
My original plan was to review each league in a separate post, but with other things going on in life right now, I'm not sure I can justify the time, at least not this month. Hopefully I'll have something before the new season starts which will give you a good shot at being profitable on Draw betting in 2019-20.
If anyone has any leagues they would like me to look at sooner, let me know. Choose from the list is on the left and I'll do my best.
Sunday, 9 June 2019
Serie B - Draw Central
Spain's Segunda División is messed up this year, with the decision in January to expel Reus Deportiu, but award 1-0 wins to their opponents in all subsequent matches.
Saturday, 8 June 2019
Avoiding Games in the Big Apple
Rather inconveniently, his funeral was scheduled for an hour before kick-off. Very poor timing, but by all accounts, the game was terrible, so perhaps I didn't miss too much.
The timing may have been intentional as, like most older Americans, he was not a football fan. His one and only live football match was the 1994 World Cup Final in Los Angeles for which his dual Grammy Award winning son snagged a couple of tickets, and it amused me to hear him describe that afternoon as "probably the most boring of his life."
Each to their own I guess. Being of rich Italian ancestry, I can't say it was the happiest afternoon of my life, but it certainly wan't boring!
I am however, a little concerned that my wife may be a closet Liverpool or Tottenham fan, as ultimately she claimed to be too ill to attend the funeral in person herself, and sent me off on my own!
For those following, here are the May updates for some of the MLB systems I've mentioned, starting with the perennially successful T-Bone System (left).
The basic version had a 19-7 record, and an ROI to level stakes of 19.8%, or 16.6% if using the American standard of betting the line to win one point.
The month included a 13 game winning run and over two weeks without a loss, so a profit on the month is hardly surprising.
For the season to date, the record is 39-19 with the level stakes ROI at 7.8% or 5.6% for American staking.
The Overs method I generously shared last month also had a profitable May, with a record of 26-19-2, and an ROI of 12.2%.
The Yankees continue to be THE public team in Major League Baseball betting. And much like Notre Dame in college football, the Dallas Cowboys in pro football, or Duke in college basketball, I've found that it's easier to, for the most part, just stay away from betting on or against these teams. However, after tracking New York again this spring it's time to call a spade a spade. And it's time to start betting against the Yankees blind.To say it mildly, it wasn't the best of predictions, as the spade turned out to be a diamond, and the New York Yankees went on to win the World Series that year.
If you had blindly backed them in every game, including post-season, you would have had an ROI of 6.4%, but the comment did make an interesting point about 'popular' teams, which is one to consider when looking to improve a basic system.
When the public bets on a name, rather then a number, there's an opportunity.
For the five plus seasons above (2014-2019), backing the New York Yankees at home when hot favourites, would have lost you 15.60 points.
This may not sound a lot out of a system that is up 208.38 points overall, but eliminating losing propositions can make a big difference to that all important ROI.
Unsurprisingly, the numbers suggest that the market especially overreacts when the game follows a Yankees win over the same opponent. Recency bias anyone?
And in case you were wondering, New York's other team, the Mets, are the absolute worst team to back as hot favourites at home over this period, costing another 17.95 points.