The Longines World's Best Racehorse Rankings (LWBRR), known as World Thoroughbred Racehorse Rankings (WTRR) before 2012, are horseracing's equivalent to World Rankings by other major sporting organizations such as ATP Tennis Rankings, World Golf Rankings, FIFA World Rankings for soccer and IRB Rugby World Rankings. The Longines Rankings are based on the ratings earned by horses running worldwide from North and South America, Europe, Middle East, South Africa, Asia through to Australia and New Zealand.
The ratings are compiled under the auspices of The International Federation of Horseracing Authorities (IFHA) by racing officials & handicappers representing the five continents who compile the ranking order by agreeing on the rating for each horse. The ratings are based on the performance of horses in elite races held during the designated period which takes in account the quality of opposition and achievements of each horse. Throughout the year the Longines Rankings are published at regular intervals and the consolidated annual rankings are released in January. The annual rankings denote the champions in the various distance categories for example sprint or mile, surface either turf or dirt/artificial and also the fillies & mares category.
According to the IFHA website, "The IFHA World Thoroughbred Racehorse Rankings are the official assessment of the top performers. In 1977, France, Great Britain and Ireland published the first internationally agreed assessment of racing merit on behalf of the European Pattern Committee under the banner of the International Classifications. In 1985, Germany and Italy joined the system, to be followed by North America (both Canada and the United States) and Japan in the mid 1990s.