Tuesday, 4 August 2020

Bees Stung - 73 Years Of Hurt

Back in April, I wrote about the 1946-47 season and how the topic of voiding it came up after a spell of bad weather, a decision that would have cost Liverpool the First Division title. 

What I didn't mention was that at the other end of the table, such a decision would have saved Leeds United and Brentford from relegation. 

The season was ultimately completed and while Leeds have since returned on four occasions and achieved some success, Brentford haven't, spending most of their time since at the third level. 

If they win the Championship Play-Off Final today, they will end a 73 year absence from the top flight, breaking the record gap of 70 seasons currently held by Bradford City.

Brentford haven't won a top tier game since beating Leeds 2:1 on 5th April 1947 (with two goals from former Crystal Palace players, in case you didn't know). 

Here are the results for the Championship Play-Offs since 2004:

And below are the outcomes from backing Favourites, Underdogs and the Draw in these games as well as in all neutral ground Play-Off matches:
A common belief among bettors is that in Play-Off Finals, with teams finishing within three (usually) places of each other (five in the National league), and the game being so important, matches are likely to be close.

The truth is that only 15 of the 67 matches to date have ended as Draws (fair odds 4.47), while the average (adjusted) Draw price is just 3.38. 

40 of the 67 matches fall into the 'close' category, but unlike in the EPL, there is no edge in backing the Draw here either. 

Sunday, 2 August 2020

Thirteen Towns

A win for Draw followers in the National League Regional play-offs where the sequence of at least one of the Finals ending all-square since 2013 was extended with Weymouth and Dartford playing out a scoreless draw in the South. Weymouth were promoted to the National League after winning on penalties.


In the North, Altrincham won 1:0 at Boston United, the first win for an Away team in a Final since 2015, to make it eleven Under 2.5 goals in the last 14 finals. 

I think someone must be reading this blog, because the Draw price in both matches shortened following Friday's post.

In the National League Play-Off, while backing the Draw is historically not a profitable strategy, I backed the wrong horse opting for Notts County, when laying the Draw would have been a better option perhaps, but Harrogate Town won the game and become the 20th 'Town' to play in the Football League, and the seventh in the last quarter of a century. They've come a long way in 40 years!
For those who like this kind of stuff, Harrogate follow these other 'Towns' Macclesfield (1997), Cheltenham (1999), Yeovil (2003), Aldershot (2008), Crawley (2011), and Fleetwood (2013) into the League since 1997.

The League (Premier and Football) now has 13 Towns and 13 Uniteds but Citys lead after Salford's promotion last year with 14. Rovers (5) and Wanderers (4) are some way adrift. 

Here are the updated results from the National League Play-Off Finals:

The usual warning that the sample size here is small, and in the neutral finals at least, one result can turn red to green and vice versa.

The FA Cup was also completed this weekend, with Arsenal again winning as Underdogs. Including League Cup Finals, the results for Cup Finals since 2004-05 are:
   

Saturday, 1 August 2020

FA Cup Final 2020

Don't believe everything you read about the FA Cup Final today. Whoever wrote the above somehow missed out on the Finals of 1975 West Ham United v Fulham, 1980 West Ham United v Arsenal, 1982 Tottenham Hotspur v Queens Park Rangers, plus the two Arsenal v Chelsea finals already this millennium. Other than that, sure, it's been 53 years...  

London clubs have actually dominated the FA Cup in the Premier League era with only seven of the 29 Finals not featuring a London club.

Three Finals have been all-London matches, and 16 Cup wins have gone to London (Arsenal 9, Chelsea 7). 

While Crystal Palace and West Ham United have both made an appearance, (both with Alan Pardew as manager), it's rather an oddity that Tottenham Hotspur haven't appeared in a Final since 1991.

It's the third Arsenal v Chelsea Final today following those of 2002 and 2017 both of which were won by Arsenal but it's Chelsea who are favourites this time, although that status didn't help them in 2017.
The H or A actually refers to the Favourite or Underdog and while the Draw is the most profitable outcome, three of the five came before 2008. 

On the other hand, in matches where neither club is odds-on, as is the case today, 50% of the (four) games ended in a Draw. 

Including FA Cup Semi-Finals, which are also neutral, we have a rather unusual situation where backing every outcome would have been positive (the result of a small sample and a couple of long-priced winners for the Draw and Underdog):


Friday, 31 July 2020

National League Play-Off Finals 2020

It's the National League play-off finals this weekend, with the Regional matches hosted by the higher seeded club.

In the North, that's Boston who play Altrincham. The hosts finished 3rd in the table, while their opponents finished 5th and when the two clubs met earlier this season, Boston won 5-0 at home.

In the South, it's a 3rd v 6th match-up with Dartford winning two Away games to win a third at Weymouth where they lost 1:3 earlier this season.

Looking at the 11 years of data for regional finals, the Draw is the profitable strategy with a 7.14 unit profit from the 22 matches, with at least one of the Finals ended all-square since 2013. Only one of those Draws had an odds-on favourite, and neither match tomorrow does. 

The play-off game for a place in the Football League next season is at neutral Wembley, where Notts County are favourites against Harrogate Town. 

Favourites since 2004 have a 5% ROI but again, the sample size is small. Notts County are the hottest favourites ever in this game (surprisingly no team has ever been odds-on) and having beaten and drawn with Harrogate Town earlier this season, are worth a bet.

Second Leg Dependencies

As expected based on the league placings, the Championship Play-Off Final will be between West Londoners Brentford and Fulham. Both clubs reached the Final in different ways. 


Brentford lost the Away leg by one goal before winning the second leg. Historically, when clubs lose the first leg by one goal, the value is on them to lose the second leg. In play-off matches of this type from 2004 on, the Away in 40 such matches has an ROI of

Fulham on the other hand, won the Away first leg by two goals. This is a margin which is also hugely profitable for the Away win, although there have only been 14 such scenarios. With a two goal margin, perhaps teams psychologically consider the job is done, and even when losing by a goal, are still ahead in the tie and don't care too much. Fulham had nothing to gain from pushing for an equaliser, and everything to lose by opening the game up, a great example of why understanding the context is so critical in sports investing. 

For those interested, the results of second leg matches ordered by the lead the Home team has going into the game are shown in the table below:
Only small samples for many columns, but some interesting trends can be seen.

The NBA restarted its 2019 season last night with a couple of close games, and as I predicted here, the value was on Unders.

Meanwhile hot favourites continue to struggle in MLB, although the T-Bone System is off to a 5-0 start with three more selections today. 

    

Wednesday, 29 July 2020

Marlins Misery

Less than a week into the MLB season, and the Miami Marlins have 10% of their fixtures postponed after 17 members of the organisation tested positive for COVID-19. Other games are being postponed and re-scheduled as a result, which makes for an interesting time for investors on the sport.


It seems improbable that this will be the only team to suffer an outbreak during the season, and with limited dates to make up games we could have a League One / League Two-like scenario where final positions are decided on win percentage with teams playing a different total number of games.

Arguably, with a record 16 (of 30) teams making it to the play-offs this year, it doesn't matter too much! 

The early games have been good for the systems, with one glaring exception being the performance of hot favourites which, after a 5-0 start on Thursday and Friday, fell apart at the weekend with a rather disastrous 2-8 record. 

Results for the season so far are below, using the American method of calculating profits 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.
Early days, and the million dollar question is will the favourites bounce back, or is this the new normal in a shortened season?

At around 1.6, Brentford may be the shortest price Home team in a Football League play-off match tonight. The top 10 shortest at this level for a second leg game are:
Some comfortable Home wins there, along with a couple of shock results with the Away team scoring four, but a shame that for Brentford's last match at Griffin Park, there will be no fans. 

Saturday, 25 July 2020

Early Season Baseball / Late Season Football

It's been a strong start to the 2020 season for followers of my MLB systems, with the Opening Day System (results updated) resulting in all three selections winning on the Money Line, and two on the Run Line, while the Hot Favourites System is off to a 5-0 start with all five also winners on the Run Line. Five more selections today, but no T-Bone qualifiers yet.


The Over / Under systems have only had one selection so far, which was a perfect winner for Unders finishing with one run scored.

Not such a good day for opposing Home favourites in the National League play-off semi-finals with four of the six home teams winning. 

We have more play-offs tomorrow and in the 17 years of Championship play-offs for which I have data, i.e. since 2004, only six times has the Away team been favourite in the first leg of the semi-final. A little surprising perhaps, given that the Away team is always the team that finished higher in the league, but there are, of course, many other factors to consider.
Whether the lack of a crowd this years has made a difference or whether it is just that Brentford and Fulham finished 11 and 8 points respectively ahead of their South Wales opponents, the fact is that both Away teams are favourites tomorrow, with Brentford the hottest Away favourite in any Football League play-off game.

Overround / Over-round

The editor of this blog likes to eschew obfuscation and espouse elucidation, and a couple of issues about "over-round" have been annoying me.

First of all, should the word be "overround" or "over-round"?  Search the web, and both spellings can be found.

Not the biggest of concerns, but without the hyphen, Blogger underlines it in red although MS Word has no problem with it. Since I have an aversion to anything red, my preference is to use "over-round". 

But the bigger issue is how to use the term accurately. 

I have seen some sources refer to an over-round of, say 103%, while other sources use 3% or 1.03. 

Logically, using the 3% / 103% as an example, the bookmakers' round is 103%, while the OVER-round is the 3%, since a 100% round would be a fair book.

My bible for all, or at least many, things betting related is Leighton Vaughan Williams' Information Efficiency in Financial and Betting Markets and here the spelling is "over-round" but the use is:

Over-round = 1.03
Dominic Cortis' 2015 study Expected Values and Variances in Bookmaker Payouts : A Theoretical Approach Towards Setting Limits on Odds published in The Journal of Prediction Markets uses "over-round" as an alternative to "bookmaker margin" or "vig". 
... adds up to more than 100%, and the difference to 100% is generally described as the bookmaker margin (Cain, Law, & Peel, 2003; Peel & Thomas, 1992; Ċ trumbelj, 2014). Other similar terms include the over-round (Zafiris, 2014) and the vig (Peel & Thomas, 1992). The sum of the inverse of probabilities are equal to 1.05121%. The bookmaker margin in this case is 5.121%.
The Mathematics of bookmaking page in Wikipedia doesn't hyphenate the word but does say that it is the "amount by which the actual book exceeds 100%, e.g. 3%:
The amount by which the actual 'book' exceeds 100% is known as the 'overround', 'bookmaker margin' or the 'vigorish' or 'vig'.
Unfortunately, this article then contradicts itself by saying:
which gives an overround of 107.36%.
Incidentally, further definitions of vigorish include juice, under-juice, the cut, the take, the margin or the house edge!

I reached out to the esteemed Joseph Buchdahl for his opinion on the matter but he must have weightier issues going on right now as he rather dismissively replied:
Well, no, it really doesn't matter that much so long as every one understands the meaning intended.

Regarding ROI, I had no idea there was a similar problem with it, as I have always used it as defined financially:
Betting Wolf explained that:
Problem with ROI is the same issue essentially... some people quoting 103% meaning 3% profit. Where as some would say 103% as in £100 spent and £203 returned.
Claiming an ROI of 103% in the above example would be rather misleading. I find it bad enough that some people don't include the stakes on their voided or pushed bets, but that's another story. 

Friday, 24 July 2020

Adjustification

A new web site appeared on my radar a couple of days ago when Toni sent me an email:

hope you are doing well. Recently, I came across your blog which I like very much, lots of useful information. My name is Toni and I run a small website on betting strategies and automation. Your "Bundeslayga" method caught my attention and I would like to ask how you adjust the lay price for the market overround and what staking you use?
The reason why I am asking is that I've tried to replicate your approach at https://sportsbettingquant.com/strategies/laying-home-favourites-bundesliga/ with some Python code but unfortunately my results differ from the ones published on http://green-all-over.blogspot.com/2020/06/bundesliga-2019-20-notes.html
After clarifying the method and the staking strategy (risk one unit on each bet), Toni responded with:
Many thanks, Cassini. Your clarification was very helpful. After adjusting my script I obtained pretty much the same result - still a small offset, probably due to rounding / lower precision floating point calculation on my side.
He then asked me for my rationale behind adjusting the odds to produce a baseline:
I am struggling a bit to understand your motivation behind using the adjusted odds as baseline to report on profit/loss figures. I mean as a Pinnacle user, I wouldn't be able to place bets at the adjusted price to achieve the reported profit/loss, would I?
Since I typically adjust the prices to a 103% over-round, and the Pinnacle over-round is (for the EPL at least) usually below this number, then certainly you could expect to beat the results shown, but the reason is primarily to be able to compare results for a strategy from one season to another, even where the over-rounds may have been 112.5% in one season (EPL 2000-01) and 102% in others (EPL 2014-17).

Clearly using the raw prices doesn't allow this. The idea and process isn't perfect of course, but as I told Toni:
...the purpose is not to give a precise P/L but rather to show where the market isn't efficient and let anyone who is interested work out how best to take advantage of that.
As I've written in the blog before, if 100 people applied any system in practice, you would get 100 different results.