Lean seems to only focuses on external customers, but what about internal customer focus?
A customer is a customer. Many organizations and/or departments have true internal customers. For example Human Resources and IT both have internal customers. These groups can apply Lean just as effectively to the internal customer.
Tracy is a Master Black Belt at GoLeanSixSigma.com, the co-author of The Problem-Solver’s Toolkit and co-host of the Just-in-Time Cafe. She is also a Lean Six Sigma Green Belt Instructor at UC San Diego and teaches in San Diego State University’s Lean Enterprise Program. For almost 20 years, she has helped leading organizations like Washington State, Charles Schwab and GE build problem-solving muscles.