Introduction to Dobbing: Part 2 geegeez.co.uk

This is the second in a short series of articles connected with betting on horse races in running, writes Dave Renham. In the first piece, which you can read here, I discussed the idea of DOBBING, which essentially means ‘double or bust’: you either double your money or lose your stake. Just to recap, here is a worked example:

Imagine you back a horse at 6.0 for £10; in order to create a potential DOB you try and lay the horse at half the odds for double the stake – so you set a lay at 3.0 (half of 6.0) for £20 (double £10). If the horse hits 3.0 or lower in running, your lay bet will be matched and regardless of the result you will win £10 (less commission). If required, there is a little more detail in the first article.

This second article will dig into the numbers in an attempt to see whether we can improve our chances of finding DOBBERS. I will look at 20 months’ worth of recent UK flat data, which equates to over 12,000 races, covering over 100,000 runners. So let’s get cracking!

Dobbing Percentages by Distance

My first port of call is the distance of the race. In terms of dobbing percentage there is a clear pattern when it comes to distance:

As we can see, the longer the race, the better the chance a horse has of DOBBING. In the first article I had alluded to the fact that this might be the case, and it is always good to see the numbers support the theory. The minimum distance of 5 furlongs gives us the lowest overall percentage (38.8%), whereas the longer distances of 13 to 16 furlongs have seen horses DOB over 44% of the time, while 17f+ races hit 45.2%.

I can think of three logical reasons why there is such a discrepancy when we compare 5f races to races of 17f or more.

Firstly, 5f sprints only take around a minute; races of 17f or more take three or four times as long. These longer races give more time for traders to spot horses that are making eye-catching progress / travelling well.

Secondly, we know that 5f events really disadvantage horses that take up a position near, or at, the rear of the field early. Hence a good proportion of slow starters / held up runners in sprints are not going to get close enough to the action at the front in time. So the chances of these horses DOBBING is relatively low. In contrast, horses that start slowly or are held up in 17f+ races have plenty of time to recover and get into a more competitive position.

And thirdly, keeping on the run style theme, front runners win around 2.5 times as often over 5f as they do over 17f+. It is easy to imagine that, in races where horses that make most or all the running over 5f, very few other runners get in a dangerous enough position to shorten markedly in price and hence DOB.

In fact, having checked that last theory, and although I only looked at 30 5f races where the winner led from start to finish, only 25% of runners dobbed in these races. That’s well below the 38.8% overall percentage for 5f races. I would not expect that 25% DOBBING figure to change too much even if I back-checked 300 races rather than 30. Unfortunately it is not something I can research quickly, therefore the modest sample.

Dobbing Percentages by Market Rank

Moving on to the position the horse holds in the betting market, and as a reminder, odds on runners have been ignored in the figures as they cannot DOB (see first article for full explanation).

Favourites DOB the most; close to 45% of the time – this is probably because a good proportion of market leaders win and, of those who don’t, most run well. I am slightly surprised to see the other market ranks relatively uniform and not sliding downwards left to right. I thought that would be the case, but there is no clear cut pattern.

Dobbing Percentages by Course

In the first article I mused on whether course configurations can make a difference to DOB percentages. Camera angles are different at certain tracks, for example, and as we know courses in this country vary massively in terms of layout. If we look at Chester’s tight bullring track…

…we can see the course is roughly a mile in circumference with short straights. Compare this now to York’s expansive gallopers’ paradise:

The circumference of the track at York is roughly double that of Chester and the finishing straight is nearly five furlongs in length.

Every track in the UK is unique – some are undulating, some have downhill stretches, uphill stretches, long or short straights, sharp bends, etc. Therefore, I would expect to see some variance across the different courses in terms of DOB%. To begin with, let’s look at the DOBBING percentages for each course.

There is a 7% differential in terms of percentages of runners successfully dobbing between Sandown at the top (46.3%) and Newcastle at the bottom (39.2%). It is interesting to note that three of the four lowest DOBBING courses are all-weather ones (Chelmsford, Wolves and Newcastle). Indeed, the other three all-weather courses also reside in the bottom half of the table. Is this down to the level of competition on the all-weather being slightly below that of the turf? Possibly.

Now we know from earlier findings that the distance of races makes a difference DOBBING wise, so maybe courses that have a lower percentage of sprint races enjoy better DOBBING percentages. Likewise do courses with a higher percentage of sprint races have poorer DOBBING percentages?

To try and test out this theory, I ordered all courses in the previous table from 1 to 37 starting with Newcastle who had the lowest DOB%. Hence I put Newcastle in position 1, Wolves in position 2 and so on up to Sandown in position 37. I wanted to use these ‘positions’ to help make the comparison.

I then calculated the percentage of sprint races (6f or shorter) held at each course during the same time frame, ordering the courses from 1 to 37, thus:

Bath top the list with over 50% of all their races being sprints, while Epsom has the lowest figure with just 15.3% of their races being at trips no further than 6f.

Having given the tracks a rank in terms of percentage of races at the course that were sprints, I could compare this with their DOB% rank. For the course DOB% to be strongly affected by race distance then the course ranks for the two variables should be similar.

In some cases they were – Thirsk for example was in position 3 in both: the North Yorkshire track had the third lowest DOB% matching perfectly with the third highest percentage of races that were sprints. In other cases, though, they didn’t match. Wolverhampton, for instance, was in position 2 for DOB%, but position 25 for percentage of sprint races. To try and show the comparison for all the courses I have created line graphs comparing their ranks. I have split it into two so that it fits on the screen:

For perfect correlation we would need to see the blue and orange lines almost follow the same path. That has not happened here taking all the courses as a whole, so we need to look to see how many courses have their orange and blue dots close to each other. 15 of the 37 courses have their two ranks varying by five or less. Meanwhile, nine of the 37 courses have their two ranks varying by 15 or more.

Thus the jury is still out in terms of saying that the course DOB percentages are affected by distance considerations. My guess is that it is a factor at some courses, but there are other factors also making a difference.

Dobbing Percentages by Run Style

To conclude this second article I want to look at possibly my most favoured area of analysis: run style. It should be noted for the run style research for this piece, I have not been able to use such a big data set, due to the time-consuming nature of this type of research. However, I have been able to analyse 4000 runners looking at how run style impacts the chances of DOBBING.

I mentioned in the first article that horses that lead for the majority of the race, or are leading at the furlong pole while looking like a potential winner, are occasions when the leader’s price is likely to shorten considerably. Obviously, if the price drops enough then the horse will DOB. Hence it would logically follow that front runners should have the highest DOB percentage. This is indeed the case as the chart below clearly illustrates. I have used the run style categories on geegeez.co.uk, and the following stats are pulled from all flat race distances from 5f to 2m 6f:

Clearly run style is important from a DOBBING perspective. Front runners DOB over 60% of the time across the test sample, and the chart clearly shows the downward trend from front of the field early to back of the field early. 4000 runners across all distances should be a big enough sample for these figures to be accurate. If I was able to look at 100,000 runners, I would be surprised if the percentages for each group changed by more than two or three percentage points. Moreover, I personally researched run style DOBBING percentages back around 2011/2012 and the percentage splits then correlate well with this newer sample.

It should be noted, however, that the distance of the race will cause slight changes to the run style DOB figures. 5-6f races will see the DOB% for ‘Led’ increase slightly to around the 64-65% mark; conversely the DOB% for ‘Held Up’ drops to under the 30% mark. In longer races of 1m4f or more the reverse happens, with the DOB% for ‘Led’ dropping to 55-56% while the ‘Held Up’ DOB% increases to 38-39%. This makes perfect sense as front runners win such a high percentage of sprint races compared to longer races and, as we know, winners will DOB except for that very small proportion that are priced under 2.02.

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That’s the end of this review of flat race DOBBING. The Run Style figures should give readers who may be thinking about employing a DOBBING strategy a possible way in. Next time, I’ll perform a similar analysis of National Hunt racing. Until then…

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