Don't Confuse TDD With ATDD

When employing practices such as Test-Driven Development (TDD) or Acceptance Test-Driven Development (ATDD), keep in mind they are not the same.  While ATDD is a relatively large effort that validates expected behavior and requires team and customer collaboration, TDD is a small effort that validates proper implementation and is often performed by a single developer (but can also be done in pairs).  Each is performed separately and provides its own unique value.