Originally, Lean and Six Sigma were seen as competing methods. The Lean approach focused on minimizing lead time for a given process, seeking speed and efficiency. Six Sigma focused on minimizing variability in a given process, seeking to minimize minimizing defects in output. Followers of each approach were quick to point out the shortcomings of the other method. A Lean process could still produce poor-quality outputs; and a Six Sigma process may not necessarily have been faster or more efficient than the process it replaced.