Articles

Lean Six Sigma

Low cost, speed and quality have long been the holy grail of businesses in an increasingly competitive environment. But it has often been claimed that low cost and speed can only be achieved at the expense of quality, and vice versa. However, with Lean Six Sigma you can have all three at the same time: lean focuses on process speed whilst Six Sigma concentrates on process quality. Six Sigma shows us that the outcomes of a process result directly from what goes into that process. So in order to improve the results of a process, we must discover and attend to the critical inputs which affect the result. Meanwhile, Lean has the goal of improving the speed of the process by the reduction of all forms of waste. So Lean and Six Sigma clearly both have much to commend them as tools for improvement, and many leading organisations adhere to one or the other, but why not combine them? The key to understanding why there is benefit in combining the techniques is to look at the shortcomings of each technique in isolation.

Lean benefits from combining with Six Sigma because:

  • Lean does not consider the impact of variation. It is the variation in a process which leads to errors, rework and customer dissatisfaction, and it is this variation that Six Sigma tackles so effectively
  • The Critical to Quality needs of the customer do not drive Lean. Lean is much more internally focused, seeking to eliminate unnecessary steps – but some steps which seem unnecessary from an internal perspective may have an unexpected and adverse impact on the customer
  • Lean lacks the cultural infrastructure of Six Sigma that does so much to make the changes sustainable.

Equally, Six Sigma benefits from combining with Lean because:

  • Six Sigma does not concentrate on identifying and removing wasteful process steps. It would simply make the processing of those steps more consistent and less prone to variation in outcome
  • There are few specific tools designed to improve the speed of processing in Six Sigma, so although effectiveness might improve as a result of lower rework, there would be little or no improvement in the efficiency of the process.

For these and many other reasons, the combination of the two techniques produces a powerful new approach and impressive results.