Today a colleague was looking for a TDD poster that showed Red-Green-Refactor with detailed emphasis on Refactoring. We found a diagram that simply said "refactoring = removing duplication". This got be thinking about a post by JB Rainsberger in which he said: "...if you master removing duplication and fixing bad names, then I claim you master object-oriented design." (If you see this, JB, do you still make this claim?)
There are lots of kinds of duplication, and JB's assertion makes sense to me especially when I think about the kind of informational duplication (as opposed to code duplication) that DRY is intended to avoid.