As a former dedicated tester and now developer, I feel that dedicated QA may not be as useful in the way software is developed these days. I like to view TDD as

As a former dedicated tester and now developer, I feel that dedicated QA may not be as useful in the way software is developed these days. I like to view TDD as "requirement-driven development". If you think of it that way, if you're not testing your logic completely, then you have incomplete requirements. Having other developers peer review seems to be a better improvement on the legacy process of dedicated QA. This means that you can't just throw commodity developers at a project; you do need people with expertise. To round it out, you do need UAT and acceptance testing but those are still variants of requirement-driven development.