How is Lean different from Six Sigma ?

While my previous blog Is Lean Six Sigma Certification any good? discusses the benefits of Lean Six Sigma and its common definitions, in here i want to give a broad overview which traces the roots of Lean and Six Sigma and what methods mainly get used in them.

Let’s Talk about Lean First:

Lean is a process improvement Philosophy which got high impetus in the 60’s onwards in Japan with Organizations like Toyota and Mitsubishi and its foundations and evolution can be traced in the TPS or the “Toyota Production System”.

Lean emphasizes on cutting down on wasteful processes and adding value added processes to improve customer satisfaction levels. Lean Enterprises strive for continuous improvements by gradual but connected quick wins. Manufacturing floors/production-areas use intuitive Scheduling and Leveling techniques like Kanban and Heijunka respectively to reduce production imbalances, and track simple and intuitive metrics like “Takt-time” (Heijunka), “Changeover Time” (used in SMED: Single Minute Exchange of Dies) or OEE (Overall Equipment Effectiveness in Total Productive Maintenance)

The figure below shows 3M, a technique used by Lean Practitioners with its origin in TPS to streamline processes …

 

Now, let’s talk about six sigma…,

Six Sigma was term coined by Motorola for their group of Project-Management and statistical techniques used to create processes with very low defect count such as 3.4 DPMO (Defects per million opportunities) for a six sigma process. Among Early adopters of Six Sigma were organizations like GE and Honeywell.

The core six sigma mechanics can be summarized via the following step by step approach called DMAIC to improve your processes. DMAIC can be considered as a project management technique as it represents the following phases of a six sigma improvement project:

1. Define: Define The Problem Objectively (What are the key data points).
   
2. Measure: Measure the numbers related to the problem (Key Process Inputs / Outputs).
   
3. Analyze: Work on numbers to see what works and what does not, how end quality is getting impacted in the current process.
   
4. Improve: Brainstorm, Pilot and Apply the data-based knowledge to improve your process.
   
5. Control: Sustain the improvements and institutionalize them.
   

Six Sigma has today evolved to encapsulate many excellent industry best practices and is an excellent set of problem solving methodologies which can be used irrespective of Industry type to improve your organizational / personal quality levels as well as an increase in customer connect and satisfaction.

The below table summarizes some of the numbers used to define various six sigma levels and what they correspond to ..