Where am I wrong?

[jtrader]

Why is that difference in calculations? Those are calculations of RBD and they are different from mines

IPLM.jpg

[napshnap]

How I'd calc it:

1) 4.7/7.2 = ~0.65, so ipp is 0.65*100=65% of sp, the drop is 65-100=-35%, makes sense cause 7.2-4.7 = 2.5 and it's slightly more than a third of the sp.

2) 15/4.2 = ~3.57 , so ipp is 3.57*100=357% of sp, the rise is 357-100=257%.

Actually I don't like how it's formulated, I'd prefer "the percentage ipp from sp" 1)~65% 2)~357%.

I think it's best to keep this % stuff as simple as possible cause otherwise it become the game of interpretation.

[foxwood]

Apples and oranges

Your calculations are measuring the difference in probability between the two prices relative to the newer IP price.

Their calculations are measuring the difference in payback relative to the original price ie originally a £1 bet would yield £6.20 and now it yields £3.70 a difference of £2.50 which is 40.32% of the original BSP value of £6.20

[Euler]

I'm not understanding the methodology there.

I always measure things in terms of chance. So if something goes off at 2.00 I would say 1/2 = 0.50

If it reaches 1.30 in-running it has traded at =1/1.30 = 0.76 or a change of 26%

[napshnap]

The real pain in the ass is calculating a % change form negative to positive number).

[Trader724]

Why is that difference in calculations?

(7.2-4.7)/(7.2-1)*100
(2.5/(7.2-1))*100
2.5/6.2*100=40.322

[foxwood]

I'm not understanding the methodology there.

I always measure things in terms of chance. So if something goes off at 2.00 I would say 1/2 = 0.50

If it reaches 1.30 in-running it has traded at =1/1.30 = 0.76 or a change of 26%

Agreed - much easier to understand the meaning of the change in price imho - simple change in probability of winning

[Trader724]

The real pain in the ass is calculating a % change form negative to positive number).

((new value - old value) / |old value|) x 100

[napshnap]

The real pain in the ass is calculating a % change form negative to positive number).

((new value - old value) / |old value|) x 100

I meant this... "For example, the relative growth between −10 and 20 is 300%, and the relative growth between −20 and 20 is 200%. Both pairs of values end at the same exact value (20), yet the absolute growth for the first pair (30) is lower than the absolute growth for the second (40), while the relative growth is greater for the first than the second."
https://math.stackexchange.com/question ... romHistory

[Trader724]

Well yeah relative growth takes into account the scale of the initial value, while absolute growth does not so they provide different perspectives on the magnitude of the change.

[Euler]

Well yeah relative growth takes into account the scale of the initial value, while absolute growth does not so they provide different perspectives on the magnitude of the change.

You aren't really interested in magnitude of change in sport, just the chance of something happening or the change in that chance.

[Trader724]

Well yeah relative growth takes into account the scale of the initial value, while absolute growth does not so they provide different perspectives on the magnitude of the change.

You aren't really interested in magnitude of change in sport, just the chance of something happening or the change in that chance.

The magnitude of change of betting odds in sports refers to the amount by which the odds have shifted from their original value.

[jtrader]

Thanks to all

[sionascaig]

I meant this... "For example, the relative growth between −10 and 20 is 300%, and the relative growth between −20 and 20 is 200%. Both pairs of values end at the same exact value (20), yet the absolute growth for the first pair (30) is lower than the absolute growth for the second (40), while the relative growth is greater for the first than the second."
https://math.stackexchange.com/question ... romHistory

Aaaarghh, you got me.... Can't get it out my head now.....

Thankfully -ve numbers don't really exist and so no need to worry about it.... Ah wait they do !

Taking refuge in the division by zero at the moment...

[jtrader]

I'm not understanding the methodology there.

I always measure things in terms of chance. So if something goes off at 2.00 I would say 1/2 = 0.50

If it reaches 1.30 in-running it has traded at =1/1.30 = 0.76 or a change of 26%

More simple,more easy an most correct

Apples and oranges

Your calculations are measuring the difference in probability between the two prices relative to the newer IP price.

Their calculations are measuring the difference in payback relative to the original price ie originally a £1 bet would yield £6.20 and now it yields £3.70 a difference of £2.50 which is 40.32% of the original BSP value of £6.20

You are quite right, foxwood! Those are their calculations,but in that 2nd when the price is drifting I've not found that method anyway.And they didn't express themselves properly - At the first they've written "The % of BSP the horse dropped/increased in running",that's mean exactly how I've calculated - and don't any percents of profit,yield,payback and etc. dropping,increasing.