HedgerPro User Guide
Introduction
POP (Popularity) compares the price with the money, using two views of a horse’s chance before the off:
- The price: the weighted average price the horse has been trading at on Betfair.
- The money: the price implied by the horse’s share of all the money matched in the market.
| POP | Meaning |
|---|---|
| Positive | The money implies a shorter price than it is trading at. It is attracting more money than its price suggests. |
| Around 0 | Money and price agree. |
| Negative | The money implies a longer price than it is trading at. It is attracting less money than its price suggests. |
The scale runs from -100 to +100, and most runners sit within plus or minus 30.
How it is calculated
The traded price
The weighted average price (WAP) is the average price matched on the horse, weighted by how much was matched at each price.
The money price
From a large set of past markets, we have fitted a curve that converts a horse’s share of the market’s total money into an implied win chance, and so into a price. For example:
| Share of market money | Implied chance | Implied price |
|---|---|---|
| 10% | about 13% | about 7.6 |
| 30% | about 25% | about 4.0 |
The curve is not a straight line. Heavily backed favourites take a smaller share of win chance than their share of the money, and less fancied horses a slightly larger one.
If the horse has less than 100 pounds matched, or the market less than 1,000 pounds, there is not enough money to judge, and POP is 0.
Comparing the two fairly
Neither set of prices adds up to exactly 100% across the field. So before comparing, both are scaled to a 100% book: each horse’s money-implied chance and traded chance are adjusted so that each set sums to 100% across all the runners.
The difference is then measured in percentage points of win chance:
gap = money-implied chance – traded chance
The POP scale
The gap is put on a square-root scale:
POP = 100 x square root of (gap / 94) when the gap is positive
POP = -100 x square root of (size of the gap / 89) when the gap is negative
| Gap (points of win chance) | POP |
|---|---|
| +1 | +10 |
| +4 | +21 |
| +10 | +33 |
| +25 | +52 |
| -4 | -21 |
The square root spreads out the small gaps, where most runners are, so small differences are easy to see.
Example
Two horses in the same race, after scaling to a 100% book:
| Horse | Traded chance | Money-implied chance | Gap | POP |
|---|---|---|---|---|
| A | 20% (price 5.0) | 24% (about 4.2) | +4 | +21 |
| B | 20% (price 5.0) | 16% (about 6.3) | -4 | -21 |
Both are trading at 5.0, but horse A is attracting noticeably more of the money than that price implies.
Where you will see it
- At the off, for each runner’s final pre-race position.
- At set times before the off (240, 180, 120, 90, 60, 30, 20, 15, 10, 5, 4, 3, 2 and 1 minute before, and at the off), so you can see how the relationship between money and price develops. At each time, only the runners still in the race at that moment are included.
Reading it
- POP compares runners within the same race. When one horse is attracting more than its share of the money, others in the race must be attracting less.
- POP is most meaningful in liquid markets. Close to the off, when the most money is matched, it gives the clearest picture.
- Watch how POP changes over the timed snapshots. A POP that keeps rising suggests money is building on the horse.
- A positive POP is a signal, not a tip on its own. It means the money and the price disagree, and the price may be about to shorten.