Race Time / Class (Weight) Relationship


There are two main schools of thought with regard to performance rating of thoroughbred horse races;

Class or Weight Rating
Each class of race is given a numerical value (in kg) and ratings are determined by taking the assigned Class value for the race, adding the WOL (weight over limit) amount and subtracting a beaten margin adjustment (kg per length x the beaten margin in lengths). This type of rating has the benefit of not being influenced by race pace, time or track conditions etc.

Race Time Rating
Each race is rated purely using race time (either overall race time or sectional time). The rating is essentially a performance measure which compares the race time against a benchmark or Par time for the track and distance. Each rating may contain adjustments for race pace, weight carried and prevailing track conditions. This type of rating does not have any race Class considerations.

Race Time / Class (Weight) Interplay

Race Time and Class (Weight) are inextricably linked. This is clearly shown to be the case by the graph shown above. As race class increases the corresponding race time decreases. The Punting Form developed time Vs class model for 1200m demonstrates a linear relationship with a correlation coefficient of 0.973 (a value of 1.000 would indicate a perfect relationship).

Determining / quantifying the relationship between the two (from scratch) is by nature an iterative process, but worth pursuing due to the following benefits;

  • An average Race Time Versus Class formula (by Distance) effectively yields a weight versus time formula which can be used to adjust ratings for weight carried.
  • An average Time Rating Versus Class formula can be used to determine a class value for new or yet to be quantified race classes and may also be used in the establishment of daily race time variant percentages (drtvp) for past race meetings. The drtvp figures are used to account for prevailing conditions, whether they be rain affected going, temperature conditions, head or tail winds etc.

The reason determining these relationships has been called an 'iterative' process, is that it is necessary to start with an assumed set of class values, determine the relationship, adjust the class values where required, determine the relationship etc. Another complication is that the time rating process relies on a Par time 'track class assessment' and a daily race time variant percentage value, which are in turn affected by the assumed values for the race class structure and its relationship with race time.

Punting Form has fully developed time versus class relationships (using the iterative process described) for both overall race times and sectional times. This modeling also enables us to determine accurate class values (in kg) for all race classes conducted in Australian horse racing (particularly useful for when race classes are changed or newly introduced, by the various racing control bodies). 


paisiosv posted this comment 09/19/2017 17:30:44 PM

OMG, that is bang on "Race Time / Class (Weight) Interplay",Ive been using a very similar system with few other factors...It does work and you will get plently of long shots with favs..