An important measure of performance
From a handicapping standpoint, earnings are an important measure which can be used to gauge performance at a specific distance, over a given surface or under various conditions of thoroughbred racing.
Since they can be indicative of the type of racing company against which a horse has been winning, earnings are often associated with Class.
However earnings are not Class or even an element of Class, they are a byproduct of it; and as such, can provide a window to view Thoroughbred Class.
Moreover, in certain races, patterns among lifetime and recent earnings can be indicative of a horse on the improve or declining; thus shedding light upon the question of Current Form.