Lean Six Sigma (LSS) is the name given to the set of best practices for achieving operations excellence.

Six Sigma refers to six standard deviations away from the mean of an observed outcome.  Six Sigma became a term denoting a process where the defect rate is beyond six standard deviations, roughly one defect in every 300,000 events.  The impression is one of near perfect quality, which is achieved by repeatedly decreasing the error rate.  The pursuit of near perfection is justified by the importance of the defect (life threatening), the potential long-run savings, the competitive product advantage or the technical knowledge gained from pursuing this challenge.

As such, Six Sigma refers to the passionate pursuit of quality excellence, incorporating all of the insights and achievements of modern quality.

Lean is short for Lean Manufacturing, a term coined to describe the Japanese/Toyota manufacturing system which emphasizes process flow and cycle time, characterized by the pursuit of zero work in process inventory, zero set-up time, unit of one production, just in time supply and minimum production cycle time.  Lean manufacturing practitioners have found that the pursuit of near zero cycle times, much like the pursuit of near zero defects, results in breakthrough process improvements that produce competitive advantages.

Taken together, Lean Six Sigma combines all of these insights and techniques into a comprehensive body of knowledge that can be used to systematically define operations goals in support of customer needs and routinely make significant progress toward achieving the goals.

Six Sigma and Lean Six Sigma have benefited from the progress made by earlier ISO 9000 and Total Quality Management initiatives.  The vocabulary and concepts overlap.  The change management pinch points are known.  The business context and rationale is well-defined.  The inconsistencies and positive relationships with financial planning and control systems are known.  Project management is a better developed supporting discipline.  True believers in the new religion better understand the limits of the new approaches and the enduring value of the older operations approaches.

Lean Six Sigma has becoming increasingly professionalized, with quality, engineering, IT, accounting, project management and purchasing professionals competing to add Six Sigma black belt credentials to their resumes.   This provides a standard approach to training and mastery of a core body of knowledge.  It provides organizations with assurance that certified professionals are ready to deliver value.

Lean Six Sigma is a terrible brand name.  To the uninitiated it sounds like a dieting sorority.  The words clash.  However, the term seems to be settling in for the long-term.  The abbreviated “Six Sigma” is incomplete and equally bare of intuitive meaning.  It may prevail in the long-term simply because it is shorter, assuming a new meaning like Kleenex, Xerox or Clorox.  The functionally accurate term “process engineering” triggers images of complex chemical engineering, pipes and boilers.   It also echoes the discredited term “re-engineering” which became synonymous with drastic cost reduction.  “Operations excellence” describes the end of LSS, but is too much of a booster term which points away from the process focus.  TQM and ISO 9000 were too narrowly focused and the terms were often discredited by emphasizing the quality assurance proof necessary for an audit rather than the improvements driven by projects.  The Toyota Production System overlaps with LSS by 90%, but didn’t gain traction as a name even when it was clearly the best operations approach available in the 1970’s and 1980’s.  “Operations management” is an accurate name but it is too bland.

Lean Six Sigma is here to stay.  Organizations which adopt these techniques and implement projects find success.  They repeat the processes with even greater success.  A beautiful process by any other name is still a beautiful process.