Numerical Rating for Tournament Difficulty

[scarr]

Has anyone attempted to define a numerical rating to tournaments with regard to how difficult they are to play. Kindof like the rating & slope of a golf course for example.

I can see three factors influencing this:

1) The competition
2) The blind structure
3) The payout structure

I have some ideas, but I was wondering what has been done before in this area.

-scarr