How is it decided if a stakes race is graded, and what grade a race gets?
I think the grade of the stake is determined in large part by the quality of field the stakes race attracts. Thus if a grade two stake is won by a horse who goes on to be a dominant horse, and other horses in that race are similarly strong, that race may be considered for an upgrade in its status, especially if this occurs over the course of a few years. Similarly if the quality of horse winning a race seems weak then the race may be down graded. Thus it is not simply a function of the purse, although one can consider there is a correlation between offering lots of money and attracting great horses. Note: my knowledge here stems from my curiosity as to why the Delaware Handicap is not a grade one race, when there are grade one races for fillies / mares with much smaller purses.
