Who has the highest "Cuba number?"

[econophile]

As I sat in the movie theater the other day and saw a trailer for Daddy Day Camp I thought, "Great! Another horrible project choice by Cuba Gooding Jr." As far as I could recall, his career consisted of one great performance (in Jerry McGuire) followed by a string of idiotic paydays (e.g. Chill Factor, Snow Dogs, Rat Race).

I then wondered if, compared to Cuba Gooding Jr., there were any other actors who had a better but a lower quality of their average body of work and how I might quantify the concept. Here's my idea: Take an actor and rank each of his performances on a scale from one to ten. Take the highest score of all the performances and subtract the overall average. For example, if we rank Cuba's performances as 9, 2, 3, 2 and 2, then his score is 9 - (9 + 2 + 3 + 2 + 2)/5 = 5.4. The highest possible score would be 10, which would mean an actor had one perfect performance and an infinite number of absolutely awful performances. I call this number the Cuba number.

My metric may not be perfect, but I think it captures the idea. Still, I'm welcome to suggestions for improvements. Another problem is deciding how to rank an actors performance. One crude way to do this would be to use the IMDB rating for each movie an actor is in, but a movie's quality often has little to do with a particular actor's performance.

A benefit of my metric is that it can be applied not only to actors, but to music groups, TV shows, etc. So, who has a high Cuba number than Cuba?