One of the really / most important elements is not taken into consideration and that is the tempo of the race / luck in running / slipstreaming, which apparently can save a horse much exertion if it lobs in behind a horse and is able to pull out at the optimum moment. Another one is fitness. How can ratings ascertain fitness, esp with those horses trained privately. Too many holes for mine ..... AND ..... the known factors which ratings use would surely be overemphasised if only for the lack of known factors from other horses.