For the past several years the following two process improvement methodologies have been combined by many companies. Here is a quick definition of both methodologies.
Six Sigma: The concept behind this methodology was about reducing the variability in the process (as measured by product specification limits) such that it performed statistically at a six sigma quality level. Performing at a six sigma level meant that the specifications were six standard deviations from the mean. Of course this is the statistical definition. A more practical definition was that your process would only produce 3.4 defects per million opportunities. In order to reach this level of quality, Motorola developed the six sigma methodology which consists of five steps.
Lean: Although the concept of lean developed as a result of automotive production best practices across the US, Japan and Germany, it is most notably linked to Toyota’s production system and its just-in-time approach to manufacturing. In order for Toyota to compete with Henry Ford’s production, Toyota focused on eliminating waste in their system. Waste in this case is defined as a process step that adds no value.
Here are the 7 types of waste:
- Over processing or processing too much
Many companies are now implementing what is called Lean Six Sigma, which is essentially a combination of both of these methodologies to help meet their process improvement goals of eliminating waste, reducing cost, and providing a quality product or service.