Six Sigma's DMAIC (see also Wikipedia) has been there before continuous procedures, so I think more or less these concepts have been nourishing itil, then CI/CD and now DevOps as well.
Still I am not sure whether we have an established data model for example to allow DMAIC across many iterations.
Question: do you know of examples of practices/ aligning DMAIC with DevOps (at the measure side, first of all)? Does it make sense?