The Mathematics of Adjustment Factor

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  • Nick JD
    Junior Member
    • Jan 2015
    • 47

    #1

    The Mathematics of Adjustment Factor

    Hi Folks, quick question:

    I'm running technical indicators on GB horse races to tune a trend bot. Thing is, my graphs are screwed up by the application of the adjustment factor on a scratched selection in the market.

    So I want to "reconcile" my bot's db to align with BF's corrected prices, so pre-scratched data agrees with post-scratched data for every market.

    However, all I can find is that if a horse is priced at 8, with a 25% reduction factor ... the price will reduce to 6.

    Sure, eight minus a quarter of eight is six, I get that bit -- but what if the price was 2, and the RF was 25%?

    Basically, should the RF use "ticks" or does the RF calculated by BF already have factored into it the size of the ticks at that particular price?

    My "price units" in my db are the_tick. Do I need to convert them back to decimal odds and then multiply by the RF to emulate BF's calculation?

    Any leads would be great! Cheers.
  • betdynamics
    Junior Member
    • Sep 2010
    • 534

    #2
    Does this help.....

    https://en-betfair.custhelp.com/app/...etail/a_id/408

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    • StefanBelo.
      Junior Member
      • Jan 2009
      • 105

      #3
      I think you should reset your trend data when a horse is withdrawn. Market conditions changes so previous data are not relevant.
      betfair bot platform, bfexplorer bot sdk

      Comment

      • Nick JD
        Junior Member
        • Jan 2015
        • 47

        #4
        Originally posted by betdynamics View Post
        It does, I think. Thanks!

        I'm assuming that BF will pay out on a price of 7.21 means that there's some type of rounding going on with regard to prices of the runners still running?

        Rounding to the nearest correct price?

        In reading up on Rule 4 ... seems it's not a precise (using "old" reduction factors on a price that's steamed or drifted etc) situation.

        The favourite on a race often doesn't have the highest reduction factor.

        Comment

        • Nick JD
          Junior Member
          • Jan 2015
          • 47

          #5
          Originally posted by StefanBelo. View Post
          I think you should reset your trend data when a horse is withdrawn. Market conditions changes so previous data are not relevant.
          Ah, but perhaps this change is relevant!

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