Friday, 12 June 2020

Drawing To A Close

Church of Betting is one of the better betting related blogs out there, and the latest post is on a topic close to my heart - Draws.

Nenko looks at how the strategy of backing the Draw in 'close' games has played out since the basic idea received attention with the publication of David Sumpter's book "Soccermatics" in 2016.

Sumpter's idea was to back the Draw in matches between the Big 6 clubs of the English Premier League, but to my mind this strategy was flawed because in any given season, one or more of those Big 6 may not be that big at all, and it seemed to me that a better strategy might be to look at matches between relatively evenly matched teams, regardless of status, where the implied win probabilities were close.

For example, in 2018-19 Manchester City were priced at 1.27 to beat Tottenham Hotspur in a Big 6 match and backing the draw in this match made little sense while ignoring matches between non-Big 6 clubs where the two win prices were perhaps identical. 

'Close' is a relative term of course, but Nenko looked at matches where the difference was less than 10%.

To remind you, the original idea recommends backing the draw in the Premier League in games where the difference of the winning probabilities of the two teams as implied by the odds (after adjusting for overround) is less than 10%. In other words, the market implies the teams are somewhat evenly matched in strength.
One flaw in Nenko's analysis is that he uses Pinnacle's Opening prices to determine qualifiers. 
A quick note: there is a small difference to my initial article since I used maximum odds among all bookmakers back then. Now I am only using Pinnacle’s opening price.
The strategy I recommend is to use the prices as close to kick-off as possible for maximum accuracy in the win probabilities of the two teams and so the Closing prices actually measure the effectiveness of the strategy as markets are not as efficient when they open (possibly weeks in advance) as they are close to kick-off.

If we use Pinnacle's raw Closing prices as our filter, over the last four seasons, including this incomplete one, there have been 108 qualifiers, with a profit of 9.42 points, and ROI of 8.7%

When I say 'raw' I mean prices that haven't been adjusted to account for the over-round. While it should be preferable to calculate the actual implied win probabilities and use these to determine qualifiers, the extra work seems to add little value as using this method there have been 105 selections, with a profit of 8.8 points, and an ROI of 8.4%.

So in the EPL, results for this strategy when correctly applied appear to be holding up, even though the genie is out of the bottle. Fortunately punters generally have short attention spans, and after a short-term dry spell will forget about the long-term profitability of a method and move on.

Looking at the 2019-20 results so far, I imagine several followers gave up at the end of January after one winner in 12 matches, but these losing runs have to be expected when it comes to backing the Draw. 

Note that matches in bold are those where the difference was less than 5%.

Similarly in La Liga, which also came under Nenko's scrutiny, the results over the past (almost) four seasons are also profitable, with an ROI of 6.7% from 96 selections.  

One noticeable change in this league is that prior to 2016-17, the Draw in 'close' matches was never shorter than 3.1. 

However, in the (almost) four seasons since, the Draw has been priced shorter than 3.0 on 14 occasions, and in no fewer than nine just this season. So far!

Backing the Draw at sub 3.0 is rarely value, and you can improve your ROI by excluding these qualifiers.

Thanks to Nenko for giving me something to write about as the pandemic plays out.

1 comment:

NotFazed said...

Does the strategy hold for other top leagues in Europe, i.e Serie A, Bundesliga ? If not, one wonders what is special about EPL and La Liga....