Tag Archive for: individual stall bias

Draw Bias 2022: Part 2

In the first article in this series I looked at how the draw can influence the market and how the market can change over time to compensate, writes Dave Renham.

Occasionally the market still gets it wrong regarding draw bias but that is increasingly rare. This is because horse racing betting markets are usually extremely efficient (by the time the race goes off, at least), not just taking the draw into account, but multiple other key factors. In this article I am going to share more draw-based research that I hope you will find interesting and ultimately useful for your own betting.

For those Gold members of Geegeez, the good news is that you are able to research the draw in two places: the Draw Analyser and the Query Tool. How you use each to study the draw is partly personal choice, but I would suggest that best insights are obtained when deploying both, not just one or the other; I use both tools for my research. Essentially, if I am just looking at the draw and nothing else I will use the Draw Analyser, but if I want to use the draw in conjunction with other factors then I’ll use the Query Tool.

When using the Geegeez Draw Analyser the stalls are split into three sections or ‘thirds’ – low, middle and high. What this means is that in a 12 runner race for example, draws 1 to 4 would be in the low third, 5 to 8 in the middle, and 9 to 12 high.

TYPES OF DRAW BIAS

I want to start by talking about types of draw bias. I believe there are two types of bias. Firstly a bias that favours a particular section of the draw; secondly a bias against a particular section of the draw. Let me illustrate with a couple of examples using draw data from 2016 to 2021. Unless otherwise stated, in this article I am going to focus on 8+ runner handicaps during this six-year period.

Pontefract 1m 2f

It is rare to get effective draw biases at distances of 1m2f or more, but Pontefract is an exception. If we look at the track configuration we can perhaps see why this bias exists:

 

 

Low draws are positioned on the inside and with an early left turn this gives them the advantage of taking the shortest route assuming they break well. In contrast, higher drawn runners are either stuck out wide round the first turn or forced to tuck in mid pack or near the back, or they need to be rushed forward to get a position thus using energy very early in the race.

There is a second left hand turn after about another two furlongs cementing the early positional advantage for low drawn runners; and there is a third turn about a quarter mile from home which again favours those racing near to the inside rail. Let’s look at the most recent six-season data now:

 

 

The stats show a clear advantage to one section of the draw (LOW); there is a significant advantage in most areas. Low drawn runners win more often, place more often, have higher IV values and higher PRB figures, too. However, backing all such runners to SP would have made a small loss and the A/E index value is lower than the middle section’s A/E value. This factor was referenced in the first article: the market at Pontefract clearly appreciates there is a draw bias. Just because one section of the draw is clearly favoured, this not in itself a license to print money! For the record, however, you would have made a small profit  of £11.98 during this period backing low draws to Betfair SP.

Pontefract over 1m 2f is an example of a bias strongly favouring a particular section. With middle draws out-performing higher draws, this is an example of a fairly linear relationship: the lower the draw the better. Draw 1 is better than draw 6; draw 6 is better than draw 10 etc.

 

 

Now for an example of a draw bias against a particular section of the draw.

Musselburgh 5f

The sprint 5f trip at Musselburgh is essentially a straight five but there is a slight kink to the left at the 3f pole which can slightly hinder wider drawn runners. With Musselburgh being a right handed course at longer distances, it means horses drawn next to the rail are the higher drawn runners. Here are the stats:

 

 

This is far from being a strong draw bias, but there is a bias against lower drawn runners compared with high and middle drawn runners. Low drawn runners come out comfortably bottom in all of the parameters as shown in the breakdown above. Looking at 2009 to 2015 we get a similar picture which gives further confidence that this is likely to continue this season and beyond.

 

 

It does seem that the kink to the left at the 3f pole is enough to make life more difficult for the wide (low)-drawn runners.

 

Indeed if we ignore 8- and 9-runner races (the smallest fields), and look at handicap races with ten or more runners we get the following results:

 

 

All of the low drawn variables deteriorate further, and such horses are winning only just above half of the races they statistically should (IV 0.53, an Impact Value of 1.00 being on par). Consequently, both middle and high draws are winning more races than they statistically should. One would expect to see those wider draws (low) struggling more over 5f at Musselburgh as the field size increases. However, it is always good to see results in black and white - as per the image above - to back up a theory.

 

INDIVIDUAL DRAWS / STALLS

A question: when you look at draw biased course and distances, what do you focus in on? The so called favoured third of the draw only? The favoured half of the draw? Or do you go further and have a preference for specific draws / stalls?

There is an argument to back the horse that is in ‘pole position’ especially on a turning track. One would think that would be the horse housed closest to the inside (i.e. drawn 1). However, the stats I have uncovered suggest differently. The stats suggest the second closest horse to the inside (i.e. actual draw 2 - 'actual' draw being the real position a horse was drawn, after accounting for any non-runners) is generally most favoured.

To show this in more detail I have looked at all 8+ runner handicaps over 5f and 6f run around a bend (2016-2021). For the record there are 12 UK courses where 5f and/or 6f races occur round a bend (seven turf courses and five on the all-weather).

Firstly I want to compare win and placed strike rates (N.B. Place SR% includes winners with the placed runners).

 

 

The margins may look quite small but they are significant as the data set covers over 2400 handicap races over 5/6f. All other key stats also point in favour of 'actual' draw 2. Firstly A/E values:

 

 

Runners drawn 2 have been far better value than those drawn 1. This is a much bigger difference than I had expected.

Next a look at profit / loss figures. Firstly a comparison of traditional SP figures (to £1 level stakes):

 

 

Losses of nearly 26p in the £ if backing all horses drawn 1 are bankruptcy territory; a smaller 8p in the £ loss for all horses drawn 2 would see a far more protracted slide to the proverbial poorhouse. But, here's Betfair SP to save the day:

 

 

The flow of bleeding has been stemmed from stall 1 but there are still bank-destroying losses; whereas trap 2 is now in the black!

But... we already know that profit / loss figures can easily be skewed by big-priced outlier winners, especially using Betfair odds. So I thought it worth comparing stats for the two draws when the Betfair SP was no bigger than 16.0. Here is what I found:

 

 

We can now see that big priced winners are not skewing the stats. Draw 2 once again has a better strike rate (both win and placed), better returns and a much stronger A/E value.

So what is actually happening here to promote stall two above the notionally best-drawn box, stall one? That is something I have pondered for many years because I have seen this type of pattern repeating time and again.

One plausible theory is that it may simply be down to the fact that horses drawn right next to the rail have less room for manoeuvre. With a rail on their inside, if they break from the stalls poorly then they are very likely to be stuck behind one or more horses. Their options are compromised until they've completed the turn by which time it may be too late. Meanwhile, horses drawn 2 have a little more space either side of them and hence more options if they break slowly. Whether this theory is true or not I obviously cannot say, but there is logic there, and it is a pattern replicated in US dirt racing at sprint distances around a turn.

What is clear in terms of the stats: in 5-6f handicaps round a turn it is preferable to be drawn 2 rather than 1.

Before moving on, I mentioned that 12 courses were in that sample and, of those 12 courses, only Kempton saw a clear advantage to horses drawn 1 over those drawn 2. Two courses - Epsom (6f) and Wetherby 5½f - had limited data (just 16 and 15 races respectively), while the other nine courses all favoured horses drawn 2 over horses drawn 1, most of them fairly strongly.

 

 

GOOD DRAWS WITH PRICE CONSIDERATIONS

As we have seen, backing a specific draw / stall under certain conditions could produce a profitable scenario. However, this idea is full of risks as we are pinning our hopes on one stall position and nothing else. So, how about combining a good draw with market factors? This is what we are going to look at next.

I have taken six of the strongest draw biases from the past six seasons (these are Chester over 5f and 7f; Goodwood over 7f and 1 mile; and Pontefract over 1 mile and 1 mile 2 furlongs). From there I have focused on the four stalls closest to the favoured inside rail: actual draws 1 to 4. Then I have ordered them depending on price. My idea is to compare price position of these good draws to see if there are patterns to be found.

By way of an example, let’s imagine the following scenario:

 

 

That would mean an order as follows:

 

 

Here are the actual results for the six course/distances (profit/loss has been calculated to Betfair SP and we are again focusing on handicaps with eight or more runners):

Chester 5f 

 

Chester 7f 

 

Goodwood 7f 

 

Goodwood 1 mile

 

Pontefract 1 mile

 

Pontefract 1 mile 2 furlongs

 

Combining the six courses we get the following results:

 

It seems therefore the best value lies at either end of the price position spectrum. The shortest priced runners drawn 1 to 4 have made the biggest profit. They have also had a decent strike rate of 28.6%. The biggest priced runner from draws 1 to 4 have also made good profits although it would have been a bit of a rollercoaster with just 13 wins from 258 runners (SR 5%).

So is this the way to go? I'm not sure, but I believe the idea is worthy of more digging in the future. I’ll add it to my rapidly expanding research list!

- DR