Ratings
This section covers the calculation of various rating (other than Speed Rating which are covered in a different section).
- Jockey ratings, using adjusted actual over expected chances.
- Trainer ratings, using adjusted actual over expected chances.
- Draw range rating, using strike rates
Actual / Expected Chance
This rating type is expected to be a pretty good indicator of the quality of jockeys and trainers because it uses the chance of each runner as reflected by their odds, compared the success rate of the runners.
The Actual success rate of a jockey or trainer is the number of winners in the period being examined.
The Expected success rate is the total of the chance of each runner in the period being examined. The chance of a runner is calculated as 1 divided by the odds (the HKJC win dividend).
There are a few adjustments that I make when I calculate these ratings, as follow
- I exclude runners where odds are greater than 10.0. Outsiders can skew the results.
- I adjust the odds to reflect the odds before HKJC take-out of 17.5%. So I divide the returned dividend by 82.5 and then multiply by 100.
- I feel that some jockeys or trainers are over-bet because of their success rate. This happens a lot and some top jockeys return poor actual / expected ratings as the expectation of a horse winning is greater than the expectation of the horse's ability without the current jockey or trainer. I am trying to calculate the expectation of the horse only, irrespective of the jockey or trainer. As such I perform the following calculation based on the strike rate of the jockey or trainer compared with the average strike rate of all jockeys / trainers.
- Restore HKJC takeout
- Odds = (Odds / 82.5) * 100
- Calculate Chance from restored odds
- Chance = 1 / Odds
- Calculate the adjusted chance based on trainer or jockey strike rate
- Chance = Chance + (Chance * ((AvgTrnStrike - TrnStrike) / AvgTrnStrike))
- or
- Chance = Chance + (Chance * ((AvgJocStrike - JocStrike) / AvgJocStrike))
- The expectation of each horse is then accumulated for the required period.
Jockey Ratings
The Actual / Expected values for jockey results for all rides in the last 12 months excluding horses with odds greater than 10.0. The result is then multiplied by 10 to give a rating integer.
The following table shows the current statistics and rating values of all current jockeys riding in Hong Kong
Trainer Ratings
The Actual / Expected values for trainer results for all runners in the
last 12 months excluding horses with odds greater than 10.0. The result
is then multiplied by 10 to give a rating integer.
The following table shows the current statistics and rating values of all current trainers in Hong Kong
Draw Ratings
The Draw ratings used are based on all runners, irrespective of odds in draw ranges of Low, Mid-Low, Mid-High and High, described as follows
Sha Tin
- Low draw range is draw of 1 and 2 and 3
- Mid-Low draw range is draw of 4 and 5 and 6
- Mid-High draw range is draw of 7 and 8 and 9 and 10
- High draw range is draw of 11 and 12 and 13 and 14
Happy Valley
- Low draw range is draw of 1 and 2 and 3
- Mid-Low draw range is draw of 4 and 5 and 6
- Mid-High draw range is draw of 7 and 8 and 9
- High draw range is draw of 10 and 11 and 12
The following table shows the current statistics and rating values of all draw ranges in Hong Kong racing.
