The term "DOB" (Double or Bust) in the context of horse race trading was first coined by Martin Kilgariff on the Patternform site sometime during 2008. The Betfair starting price was introduced in December 2007. Initially the term “DOM” was used (Double Our Money), but this was a bit presumptuous, and was discarded after a few day with the more punchy DOB replacing it.
At it's simplest DOBBING is about betting on price movement rather than the actual race result - i.e. trading. What DOBBING does is to simplify the concept into a pair of transactions which has the potential to change any runner in a race into an even money chance.
Changing any runner into an even money chance wouldn't be a very good move is we were talking about WINNING the race, but we aren't - we talking about making any runner an even money chance to hit a particular price In Running. As long as our runner trades low enough In Running (IR) we WIN irrespective of the result.
So where does the term DOB come from - well it comes from the phrase Double Or Bust. We either double our stake or lose the lot i.e. bust.
OK, What make up a DOB. - There are two bets which make up a DOB:
A BACK bet which is placed before the race begins, and
A LAY bet which is usually matched In Play but can be matched pre-race if the selection is heavily supported.
This is how it works: -
Where you back a runner at, for example, 7.0 for a tenner pre-race. This gives you a potential profit of £60.
You then lay it back In Play at half the price (3.5) for double the stake £20. A potential loss of £50.
If during the race (In Play) the lay bet for 3.5 is matched, then you win £10 no matter what the result.
Lets look at the possible outcomes.
1) - your horse runs like a donkey - it never gets into the race and the In Play price get nowhere near your 3.5 - You lose £10
..... your £10 win bet loses so we lose £10
..... your £20 lay bet at 3.5 isn't matched so you win/lose £0
..... You lose £10, but win/lose £0, so on balance you lose £10 (£0 - £10) - which is Bust.
2) - Your Horse Loses, but runs well and trades down to 2.3 In Play - You win £10
..... your £10 win bet loses so we lose £10
..... your £20 lay bet at 3.5 wins (i.e. the horse doesn't win but In Play drops below 3.5) so you win £20.
..... You lose £10, but win £20, so on balance you win £10 (£20 - £10) - which is Doubling your £10 stake.
3) - Your Horse Wins, trades down to 1.01 In Play, - You win £10
..... your £10 win bet at 7.0 wins so you win £60
..... your £20 lay bet loses (i.e. the horse win) so you lose £50. (your lay was 3.5 to £20 - a liability of £50)
..... You win £60, but lose £50, so on balance you win £10 (£60 - £50) - which is Doubling your £10 stake.
Hence Double Or Bust.
This works for any priced runner as long as the price is 2.02 or greater.
Back at 30 for £5 - Lay at 15 for £10 - £5 profit if it DOBS
Back at 2.6 for £20 - Lay at 1.3 for £40 - £20 profit if it DOBS
Back at 4.8 for £2 - Lay at 2.4 for £4 - £2 profit if it DOBS etc.....
So how do we go about selecting a runner we expect to DOB?
One approach is the pace angle. The longer a runners keeps the lead the more likely it is to DOB. Pace information can be found on the pace page for each race.
The other main approach I use is the form approach, but this time rather than looking at the finishing position a runner has achieved in the past I look at how low it has traded and whether it managed to DOB from it's BFsp. The Betfair/Timeform page http://form.horseracing.betfair.com/timeform.
In the same way that I use patternform to filter out previous race I've modified Patternform to show how well a runner has performed in it's previous by In Running Price which I call Moneyform - i.e. using price movement as a form descriptor.
When we study form there are a multitude of tools available to help us with out selection process. Hcap ratings, Speed figures, draw analysis etc etc. When we study a race we utilise these tools to try to understand the quality and preferences for each runner. There isn't the same abundance of tools available for In Running analysis. Timeform have an approach and betfair publish the In Running Low prices with limited filtering. To help with this aspect of DOBBING study I've developed a couple of tools - an Overview Table, and Moneyform
This table Holds for each runner in each race a line of moneyform figures for it's last 10 runs and the percentage of time it has DOBBED in those 10 races. If for any reason I don't have a moneyform figure for a previous run (foreign race, BFsp less the 2.02) I include enough previous race such that I have valid moneyform figures for 10 previous runs.
A Moneyform figure indicated two things - firstly whether a runner has DOBBED in a particular race (i.e. has it's In Running price Fallen to 50% or less than it's BFsp approximation) and how low an IR price was matched (to at least £100).
The MONEYFORM values are as follows
* is a 1.01 which usually means a win
1 is 1.99 to 1.02
2 is 2.99 to 2.0
3 is 3.99 to 3.0
4 is 4.99 to 4.0
9 is 5.0 or over IR but less than half it's BFsp price i.e. DOB
- A blank value means I don't have the data available (I might change this to another character)
This though is only a rough indication of how a runner has performed from a DOBBING perspective since it doesn't take into account the type or race etc, and a much fuller and more versatile tool is described in the next section
The patternform card has been amended to include the Moneyform figure rather then the formfigure for each runner. The win% column is really a DOB% column (and will be modified when I get time). So you can perform all the usual patternform analysis but this time you'll be able to see how the IR price has performed
The Moneyform tool should allow you to look for DOBBING candidates with ease, but remember the final selection is still your own choice and just bacause a runner has dobbed in the past is no guarantee to how it will perform today.