I am preparing for a Green Belt certification and I am a bit confused about when to use Lean tools versus Six Sigma tools. My understanding is that Lean is about speed and Six Sigma is about accuracy, but they seem to overlap so much in the "Lean Six Sigma" methodology. Can someone explain with a practical example how a company would use both to solve a customer service response time issue? We want to ensure we aren't just fast, but also consistent in the quality of our support.
3 answers
Think of Lean as the tool to "clean up" the process by removing unnecessary steps, while Six Sigma is the tool to "fine-tune" the remaining steps. In your customer service example, you would first use Lean to map the process and identify "Muda," such as a ticket being routed through three different departments before reaching a technician. By removing these extra handoffs, you increase speed. Then, you use Six Sigma’s DMAIC framework to analyze the variation in response times. If some tickets are solved in 1 hour but others take 48 hours for the same issue, Six Sigma helps you find the root cause of that variance to ensure a consistent, high-quality experience for every customer.
Does your training cover the "DMAIC" phases deeply enough to help you decide which statistical tools to use during the 'Analyze' phase for identifying response time variances?
Lean is the "What" (process flow) and Six Sigma is the "How well" (accuracy). You need both to achieve operational excellence in any competitive industry.
Great analogy, Barbara. It’s hard to have one without the other. If you have a fast process that produces errors, you're just making junk faster!
David, we’ve been looking closely at Pareto Charts and Histograms. For our service desk project, we used a Pareto Chart to realize that 80% of our delays were caused by only 20% of the ticket types. This allowed us to target our Six Sigma "Analyze" phase specifically on those complex issues rather than trying to fix everything at once. By using a "Control Chart," we can now monitor our daily response times and get alerted the moment the process starts to drift outside of our 3-sigma limits, which has helped us maintain the consistency Brandon mentioned earlier.