Hello from smouldering Canberra. Here is an attempt at a "Dummies guide to TAB pools" - hope this helps.

Lets start with the simplest - the win pool. An example is probably the easiest way to demonstrate so I am going to assume an 8 horse race. Each horse has the following amount bet on it:
1. $100
2. $70
3. $60
4. $55
5. $50
6. $30
7. $25
8. $10
The "pool size" as reported by the TAB is simply the sum of the amounts bet on each horse - in this case the pool size is $400 ($100 + $70 + ... etc). To work out the dividend for each horse the first thing the TAB does is take out their cut - for the win pool this is around 14.5% (this is for Supertab - I think the others are around the same). The TAB therefore takes out $58 (14.5% of $400) and the remaining $342 is available to be paid to the lucky winners. Each dividend can then be worked out by dividing that $342 by the amount bet on each horse and then rounding down to the nearest 10c. So the dividend for horse 1 would be $342/$100 = $3.42 = $3.40 (after rounding). So the dividends for our 8 runners would be:
1. $3.40
2. $4.80
3. $5.70
4. $6.20
5. $6.80
6. $11.40
7. $13.60
8. $34.20

One thing to note is that because the TAB rounds down the effective take-out percentage is more than the 14.5% - in the case of the win pool it averages about 15% - with place pools it can be a little higher (this is because the lower the dividend the greater the rounding effect is).

Knowing the above information we can also work backwards to work out how much of the win pool is invested on each horse if we know the dividends. To do this we divide 1 by the dividend and then multiply by (1-TABTake) - in this case you need to use the adjusted TAB take of 15% so 1-0.15 = 0.85

If we look at horse 1 in the above example we have:
(1/3.4) * (1-0.15) = 0.294 * 0.85 = 0.25
So horse 1 has 25% of the pool invested on it (25% of $400 = $100)

For horse 2 we have:
(1/4.8) * (1-0.15) = .208 * 0.85 = .177
So horse 2 has 17.7% of the pool (17.7% of $400 = $70.80)

Due to the rounding you will not get exact investment figures when you do this reverse calculation but it is close enough.


The place pool works basically the same as the win pool except there are, of course, 3 dividends instead of 1 (assuming 8 or more runners).

Lets assume that the same amount was bet on each runner in the place pool as the above win example (so again $400 total with $100 on runner 1, etc). Again the TAB takes their cut first (same percentage as win pool) so we have $342 to be split between the 3 place getters. To work out the dividends we first divide the pool by 3 to get the amount to be paid to each winner - $114.

Each dividend can then be worked out by dividing that $114 by the amount bet on each horse and then rounding down to the nearest 10c. So the dividend for horse 1 would be $114/$100 = $1.14 = $1.10 (after rounding). So the dividends for our 8 runners would be:
1. $1.10
2. $1.60
3. $1.90
4. $2.00
5. $2.20
6. $3.80
7. $4.50
8. $11.40

Again we can also work backward to find out how much is bet on each horse based on the dividend. We use the same formula as the win pool except we divide the final answer by 3 (or 2 if there are only 2 places being paid).

If we look at horse 1 in the above example we have:
(1/1.1)* (1-0.15) / 3 = 0.909 * 0.85 / 3 = 0.258
So horse 1 has 25.8% of the pool invested on it (25.8% of $400 = $103)
Again the rounding effect gives us the error in the pool amount.

I hope this is helpful - I don't have time at the moment to go any further with how you might use this info but if anyone has any questions I will do my best to answer them when I get a chance.



_________________
"Computers can do that????" - Homer Simpson

[ This Message was edited by: becareful on 2003-01-20 15:36 ]