Double_stake_volume Query

Developers
#1

Hello, I run a moderately popular Specials betting website called TellyStats. Up until now we’ve only ever pulled odds from Betfair but would like to expand to taking odds from Smarkets via the API.

The problem arises in that Smarkets measures volume differently to just about any betting site I know, and I’d like to display Smarkets’ volume in a way people understand - that volume is the amount of money matched (i.e, not with added liability).

If I look at the volume API endpoint for Dancing On Ice, before I placed a bet, the volume was this:

{
  "volumes": [
    {
      "double_stake_volume": 89,
      "market_id": "17719250",
      "volume": 431
    }
  ]
}

I then put down £2 at 9/1 and the volume changed to this:

{
  "volumes": [
    {
      "double_stake_volume": 93,
      "market_id": "17719250",
      "volume": 451
    }
  ]
}

The double_stake_volume key increased by £4.
I’m not keen to use the ‘volume’ key because I don’t believe it to be a very good measure of volume, but the double_stake_volume metric seems like I can just halve that figure to get the actual traded volume, right? I’m also unsure why there even is a double stake volume metric? Why double it?
The API docs describe double_stake_volume as: It is the twice back stake for every execution., but I don’t quite understand what that means. Is an execution a bet?

The Problem:
I was going to use half the double_stake_volume to measure volume but a friend of mine has just told me he put down a total of £75 on the American Song Contest outright across 3 selections, however the double_stake_volume on that market is only 80, whereas I believe it should be at least 150 based on his bet. What’s going on and what am I misunderstanding?

{
  "volumes": [
    {
      "double_stake_volume": 80,
      "market_id": "19455433",
      "volume": 1120
    }
  ]
}

To add to my confusion, the chart on the American Song Contest page looks like about £130 has been matched. https://smarkets.com/event/42518816/tv-and-entertainment/american-song-contest/american-song-contest-2022-winner

Can someone help me understand what’s happening here?

#2

Hi Daniel, thanks for posting. We use the calculation we do for our headline volume figures as we feel it provides a more accurate representation, being the total staked across the bet between two parties. I may be wrong but I believe only one exchange uses a different calculation for their headline volume figure.

In any case, we do appreciate this can make things difficult for direct comparisons with that other exchange and that’s why the double_stake_volume figure exists. This calculates volume in the same way the aforementioned exchange does in that a £2 back bet at any odds results in an increase of £4 in volume. As such you don’t need to half the double_stake_volume figure to have something that is directly comparable unless you are halving their volume figure as well when doing the comparison.

In terms of the specific market you are reference here, the volume figures returned in the example there look correct. If your friend placed the bet using SBK this may explain the discrepancy though, as those figures only track exchange volume.

I hope that helps but if you’ve any further questions please just let us know.

#3

Thanks very much for the info, my friend had indeed used the SBK for a portion of his bets and he exchange for others which was the primary source of my confusion.
I think he was thrown off that apparently bets made on the exchange and the SBK both give the P/L on the exchange even though the volume for only one platform is registered.

Also you’re correct that a £2 bet does indeed increase the amount matched on ‘the aforementioned exchange’. That was my error, 11 years of using the site and never even noticed…

Anyway, thanks for the explanation. I’ll use the double_stake_volume key.

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