The World's Best Horse Race is based on criteria used by the IFHA for its annual listing of the top 100 group 1 and grade 1 races for 3-year-olds and older. The ranked list was compiled using the annual race ratings, an average of the World's Best Racehorse Rankings ratings of the first four placed horses in each of the past three years. 

 

The Arc, run each October at Longchamp, achieved the highest rating of 125.75 for the years of 2013-15. Treve, the co-highest rated horse in the world in 2013, won in both 2013 and 2014, while the 2015 edition went to Europe's Horse of the Year Golden Horn.

 

Second on the top 10 list was the Breeders' Cup Classic (124.33), won this year by Triple Crown winner American Pharoah  , who Jan. 19 was named the 2015 World's Best Racehorse, while the Breeders' Cup Turf (122.50) and Irish Champion Stakes, each rated 122.50, to rank a joint-fourth, 

 

Among other top 10 races, the Juddmonte International Stakes (122.67) ranks third; 6th, Prince of Wales's Stakes (122.25); 7th, Japan Cup (121.25); 8th, Prix du Haras de Fresnay-le-Buffard-Jacques Le Marois (121.00); 9th, Queen Elizabeth II Cup (120.83); and 10th, Champion Stakes (120.75).

 

The top-rated races in the five respective distance categories of Sprint, Mile, Intermediate, Long, and Extended are the Darley T.J. Smith Stakes (119.33-Sprint),  Prix du Haras de Fresnay Le Buffard-Jacques Le Marois (121.00-Mile), Breeders' Cup Classic (124.33-Intermediate), Qatar Prix de l'Arc de Triomphe (125.75-Long), and Tenno Sho (Spring) (118.08-Extended). 

 

The Belmont Stakes (119.92), took first place as the world's top 3-year-old race for 2013-15, followed by the Kentucky Derby (119.83). The two U.S. classics ranked 17th and 18th on the top 100 list while the Preakness Stakes (117.50) was 53rd.

 

The top race for fillies and mares is the Qatar Prix Vermeille (117.00). 

 

Because of a three-way tie for the final spot on the list of Top 100 group I or grade I races, the 2015 edition consists of 102 races. 

 

Twelve countries comprise this year's list, representing the foremost racing events throughout the world across 39 different racecourses. Australia leads all countries with 23 total races, followed by the United States of America (21), Great Britain (17), France (10), Hong Kong (10), Japan (10), United Arab Emirates (4), Ireland (3), Canada (1), Germany (1), Singapore (1), and South Africa (1).