Six Sigma and Lean are two common methods under continuous improvement umbrella that businesses use to help improve quality and efficiency. They truly compliment each other and if applied in union, yields powerful and profitable results for the company.
I am working in continuous improvement space for over 8 years now, first as Black Belt, then as Master Black Belt and now as Global Leader for CSI function. I have used different methodologies at different times and different situations to yield results and all of them have helped me deliver great value to the business.
Even after so many years, one topic that has come up again and again and intrigue me is the ongoing debate regarding Lean vs Six Sigma, its merits & which one should be followed while streamlining business processes and eliminating waste out of process.
Even among experts, both these approaches have their propagators and detractors who will debate endlessly and cite various situations in which one approach may produce better results. While all of them are right, in my experience its the combination that yields higher profitability with consistency and stability.
Lean focuses on cutting out or minimizing non value added (NVA’s) and eliminate wastes out of process so that only steps that directly add value to the product and some critical steps that adds value to business are performed. Lean identifies value added steps from customers perspective. It identifies it asking a simple question if customer would be willing to pay for it. If yes, it is a value added steps else it could be NVA or waste. This method does leave a highly streamlined and profitable process in place that will flow smoothly and efficiently however, the problem that arises from it is a lack of quality. By completing value added activities quickly, without appropriate checks and controls nurtures an process prone to errors which then requires rework. This is another waste identified under Lean umbrella and this is there Six Sigma steps in to eliminate black noise/ special causes of variation and bring on business process optimization. I have seen the best way is to streamline process through Lean methodology and to eliminate process defects sub six sigma projects be taken up for optimization. It is crucial that while taking up Lean projects, statistical approach is not left completely out of context and used in sync.
The Six Sigma methodology emphasizes reducing the variation thus reducing defects or errors in a process. It focuses on identifying variation in the types of data inputs to control the output. To identify inputs to process you would need process experts using methods like Fish-Bone analysis done often by brainstorming exercise to do Root Cause Analysis to determine the source of errors. There are numerous examples of companies benefiting from six sigma implementation and achieving competitive edge in market.
We need to be careful about giving targets to employees about doing projects because with targets often for low hanging fruits also six sigma projects are taken up. What I have noticed is the use of statistical approach with vast amount of data gathering, validation and statistical analysis when there was a practical solution available and known with or without a simpler analysis. This is a simple waste of resources. While the results will still be positive for the organization, they could have saved more by scrutinizing projects. Lean practitioners also would work a project and leave it sub-optimally improved don’t attack variability. This makes role of MBB a crucial one who will help organizations get maximum results through each and every process improvement project. Thus it makes sense to have both Lean and Six Sigma projects should be mentored by MBB.