GTX Ratings

GTX Ratings are generated from a formula and do not rely on any other variables such as bonuses or penalties to be added or subtracted. Many of these variables will already have been used in the formula to create the rating.

The GTX Rating formula was derived using logical rules entered into what is called an ‘Expert System’ and optimised using Artificial Intelligence.

A couple of published definitions of an ‘Expert System’...

  • ‘Expert knowledge is a combination of a theoretical understanding of the problem and a collection of heuristic problem-solving rules that experience has shown to be effective in the domain. Expert systems are constructed by obtaining this knowledge from a human expert and coding it into a form that a computer may apply to similar problems.’  [George F. Luger, Artificial Intelligence: Structures and Strategies for Complex Problem Solving, 4th Edition, 2002. Addison-Wesley. Section 1.2.3 - Expert Systems]
  • ‘An expert system is a computer program that simulates the judgement and behaviour of a human or an organization that has expert knowledge and experience in a particular field. Typically, such a system contains a knowledge base containing accumulated experience and a set of rules for applying the knowledge base to each particular situation that is described to the program. Sophisticated expert systems can be enhanced with additions to the knowledge base or to the set of rules’  [www.whatis.com]

The GTX Rating formula was replaced in July 2005 with a new and enhanced algorithm that 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.

Additionally, the GTX rating is dynamically altered when track conditions are downgraded or when jockeys are replaced.

The GTX Market Parameters, located under Setup>Ratings (Extended), include a parameter called 'Market Distribution'. This setting can be altered to suit the user but it is important to note that altering the ‘distribution’ will alter the GTX Net Ratings assigned to each horse and also the difference in Net Ratings between each runner in a race.