A Brief Explanation of Ratings
All ratings offered within GTX are generally derived from historical form. However, each uses a different methodology based on an individually developed model. Most ratings use an age old method of identifying what is called a Qualifying Run (QR) where the program selects a past run likely to be representative of what could reasonably be expected of that horse today. Each rating process has different criteria for selecting the QR.
The GTX Rating formula was replaced in July 2005 with a new and enhanced algorithm which now uses some 60+ variables in several parameter sets, for example different weighted values used for each variable for say, 2yo races and hurdle races. Unlike the former GTX Rating formula, the new formula gives a rating to horses having their first career start where information is drawn from the sire’s history, the trainer’s history, the jockey and several other known factors.
Weight Ratings are sometimes referred to as a ‘Class Ratings’. This method was originally developed by renowned racing author and ratings expert, Rem Plante in the early 1960's and published in his book ‘Australian Horse Racing and Punter's Guide’.
These are form-based and time-influenced ratings that are calculated at the post race results stage by an artificial Neural Network and manually adjusted by a form handicapper. Each historical run has a rating assigned to that run. The GTX program selects a QR (qualifying run), or what is in effect considered to be the most suitable historical run from the last 16 form runs. The value stored against this run determines the Base Rating.
Ratings are expressed in ‘points’, generally within the range of 0 - 70 points. Each point equates to 1/10 second, or 0.65 lengths, but is variable by distance of race. The GTX program selects a Trakline QR (qualifying run) from what is considered to be the best of (generally) the three most recent runs. If the horse is resuming from a spell the QR is chosen from a previous first up run. The value stored against this run determines the Base Rating. If default settings are used, GTX starts with the base rating then adds a consistency bonus, subtracts a jockey penalty and either adds or subtracts a value to compensate for the acceleration/deceleration effect (ADE), and a value for ‘Other’, but does not add the weight over limit or the jockey allowance. The consistency bonus is not added for two-year-old races.
These are pure time-based ratings derived by a process of comparison of each horse’s runs against a standard (a par time) for each track and distance-adjusted for track variant. Ratings generally fall within the range of 25 - 70 points. Each point equates with 1/10 second, or 0.65 lengths, (but is variable by distance of race). The GTX program selects a Trakform QR (qualifying run) from what is considered to be the best of (generally) the three most recent runs. If the horse is resuming from a spell the QR is chosen from a previous first up run. The value stored against this run determines the Base Rating. If default settings are used there are no bonuses or penalties.
Base ratings for horses having their first race start are derived using a formula based on jockey penalty and class value whereby the stronger the Class Value (CV) and the better the jockey, the higher the rating.
Time Rating calculated using a process and formula developed by Garry Robinson of Winform Publishing. For information on Winform Ratings please contact Garry on 02-4950 1747 during business hours.
As indicated by the name, Combined Ratings are derived by the combination of the values of any two or more of the above ratings (but not including GTX Ratings) in user-specified percentage weightings. Possibilities range from combining two rating methods in a 50/50 or other percentage, to using four of the currently available ratings in any percentage mix.
Early analysis of multiple combinations revealed a most effective combination to be:
One user reported good figures over several years (excluding jumps races and races with first starters) using the following mix:
Warning : When creating a Combined Rating do not tick the option ‘Rating is tuneable’ unless you understand the ramifications. This option was added at the request of one user who wanted the combined rating graphs to reflect the combined rating for every historical run and then fine-tune (adjust) the base predictive rating using the past ratings as a guide.
If you choose this option you must fine-tune the base rating for every runner in every race, manually, as each horse is rated with the Formline base rating only. This base rating is the starting point for adjustment. If you are not prepared to do the work of manual tuning, then the Tuneable Combined Rating is not for you.
These ratings are publicly available information published on the Unitab web site. GTX enables you to view the ratings, and test them through the System Developer, not only as a rating value which generally ranges from about 70 points to 100 points, but also as a probability and a price.
In its native form, this rating does not include any bonus or penalty adjustments. However, the GTX user is free to experiment with this rating by adding the bonuses and penalties within GTX, such as Jockey Penalty, ADE, Consistency, and Barrier Penalty. It is therefore possible for the user to create a new rating that is not used by any other user. There is nothing to stop you from assigning a value to the ADE, although it is not really ‘ADE’ for ratings without QR's.
Originally conceived solely as a visual indication of whether or not a runner should be backed, Traffic Lights is now a powerful user-definable rating which is arguably the single most powerful feature in GTX.
The Traffic Lights have a considerable advantage over a system, in that a system rejects a horse unless all rules are satisfied, whereas the Traffic Lights calculate the horse which best meets the user’s criteria, giving a quick visual indication as well as a detailed numeric value if required.
To create the rating, the user may configure any of the 235 available parameters, including the TAB price rankings. A net value for each horse is derived, which is treated by GTX in exactly the same way as any other net rating, in that a probability and price are calculated.