The jockey posting the best results for a racing season is awarded a jockeys premiership.
For trainers, the one with the best results over the course of the racing season is given the trainer’s premiership.
Australian Jockey Premierships are awarded to jockeys in several categories.
For example, there are jockeys premierships for every state in Australia and jockeys premierships for each of the metro racing venues, such as Melbourne, Sydney, Brisbane, and so forth, to go along with premierships for Australia, New South Wales and so on. Further, there are also premierships for the provincial, country and picnic races, but premierships are not one of those everyone-who-participates-gets-an-award situations.
There is a jockeys premiership for the entire country and the winner of the Australian Jockeys premiership will realise more interest from trainers and owners in having him or her ride the best horses from those stables. There are also some jockeys’ premierships for apprentice jockeys.
The entire last paragraph applies to trainers and trainer’s premierships, other than the part about riding and apprentices.
It is something of a self-perpetuating accomplishment.
Winning a Australian jockeys premiership or a trainers premiership for the first time makes it easier to win for a second time.
An example of this from a bygone era would be the case of trainer T. J. Smith. He won his first Sydney trainers premiership in the 1952 - 1953 racing season. He was challenged, but never bested for the next 33 years.
The current day analogy to T. J. Smith is Chris Waller.
Chris Waller has won the Sydney trainers premiership on multiple occasions.
Australian Premierships are determined on a points system.
The Spring Premierships scoring system provides an example of how a premiership is determined.
Winning a race classified as a Major Race earns 12 points, while second is worth four points and third two points. The winner of a Feature Race is credited with six points for a win, four points for second and two for third. Standard Races are worth three, two and one points, respectively.
Pretty basic, other than for some provisions for dead heats and protests.
In the event of ties, a count-back system comes into play.
Jockeys premierships and trainers premierships provide punters with useful data. The winners of an Australian jockeys premiership or a Australian trainers premiership is a source of prestige for jockeys and trainers. Winning an Australian horse racing premiership in any category is a highly sought accomplishment and a benchmark of success.
Two horses, equal in ability in all ways, will have different prices with a premiership jockey in the irons. Same for trainers. The actual difference in the odds will usually be minor, but over the course of a season or a career, that little difference adds up.