If you use historical data to build your own betting systems then it is likely that you use either SP (Industry Standard starting price) or BSP (Betfair Starting Price) for results.
This is fine until you build a price sensitive system or a system that relies on being on a particular ranked runner, like the favourite.
If we take BSP as an example we can see the issues that could arise.
We have to remember we don't know what BSP (or SP) price will be until it is announced when the market goes in-play. You could argue that the ranking a few seconds before the off will tell you who the first, second, third ranked runner will be.
Often this isn't the case. The BSP ranking can be different to the ranking before the off.
A short test I did some time back showed the rankings were different as many as one or two times in 10. This might not sound a lot. But when you are talking about hunrdreds or even thousands of bets over the course of a year this could severely warp the results you were expecting.
The same is true of price. The price before the off is often different to BSP causing even more inaccuracies in your system.
So what is the answer?
When the market goes in-play Betfair's BSP price and ranking is available through the API. We have developed a new feature on the Grey Horse Bot that allows you to get the BSP price and Ranking when the market goes in-play. The software allows you to choose which ranked runner to bet on to only place a bet into the market if it is within the price range you require.
Of course we can not get around the fact that Betfair can match a back bet up to [999.0] or lay bet as low as [1.01] but using the Grey Horse Bot will could get you closer to BSP.
The software also allows you to use the standard BSP features automatically as well. When you create your own system it should be part of your testing to determine if you get better prices before the off or in-play. You can test both automatically with the Grey Horse Bot.
For a selection of Betting Apps for Betfair.com please see the Betfair App Directory