'' Sole criteria?''
''People who are participating in this thread are debating the quality of the actors (and where you have them ranked) and those actors abilities -- you are debating the quality of their movies.''
What I'm more often than not doing is mentioning some of their standout roles---and on occasion their lesser roles----while responding to comments on specific actors. It's give-and-take depending on what's said about whom. I use the film comments to support WHY I ranked them higher. But since we already have five previously mentioned qualifications, most actors are listed to begin with because most have between 3-4 of these qualities.
movies are not the criteria. A body of work often is. Many of these guys have longevity, among other factors.
My other rationale is only temporarily secret, and it's nothing earthshattering.....it involves additional specific films and statistical support. I think it better to save that for the end, in order to keep the topic going a few extra days after the list is done. It won't be a Kevin Spacey head-in-the-box routine, but it will reinforce my choices. To explain them now would give away the identities of the final 18, so na ga da. Not going to do it. Wouldn't be prudent. Don't drink either. Never touch it. Thousand points of light. Read my lips......