(I’ve been asked to provide a down and dirty explanation of what Lean Six Sigma is; so hope this helps. If you have any suggestions, feel free to let me know, thanks!)
Lean Six Sigma combines two business management strategies: Toyota’s Lean manufacturing and Motorola's Six Sigma system. While Lean focuses on creating more value with less work, Six Sigma system defines, identifies and eliminates defects in product design and development; a method that accelerates the decision-making processes, reducing inefficiencies and increasing quality.
Lean Enterprise was developed by James Womack, John Krafcik and Daniel Jones, brain trust engineering professors at MIT that aims at optimizing the production process by reducing cycle time; identifying the value of a product from a customer's perspective and costs of development. Based on principles derived Ed Deming and his Total Quality Management Theories, Japanese manufacturing industry incorporated these concepts and adopted into the Toyota Motor Corporation. Lean is oftentimes referred to as TPS or Toyota Production Services.
Three types of waste have been identified by Toyota: muda “waste”; mura “uneven”; and muri “over processing". Lean manufacturing places greater emphasis on activity than on design or implementation. TPS has further identified seven deadly wastes popularly known in the industry as TIMWOOD, an acronym: Transportation; Inventory; Motion; Waiting; Over Processing; Over Production; Defects (and/or rework). Costs attached to each of these types of waste have been measured to be significant and are either passed to customer or recorded as a loss.
Bill Smith and Motorola created the Six Sigma business management system. This practice relies on statistical analysis to optimize an organization's production process. Those that undergo a stringent training process, like many martial arts forms, identifies and certifies knowledge levels with a color belt systems, the black belt being the highest level. What’s confusing is that Lean is a Japanese process and does not require this form of certification. With that said Six Sigma is validated in many Quality Manuals measuring the number of defects during a process with a goal to score no more than 3.4 defects per million.
Six Sigma seeks to eliminate defects through a process called DMAIC: Define; Measure; Analyze; Improve; Control which is different from Lean.
By combining the ideas, Lean Six Sigma creates a dynamic but yet scientific management process that increases production speed while decreasing variations. Lean is preferred by an organization to fine-tune its daily operations, while Six Sigma is used on the production process. So Lean decreases production waste, Six Sigma implements procedures that increase product quality.
Together Lean Six Sigma gives companies an effective method to address issues of speed, quality, and cost and eliminate steps that are wasteful while opening up opportunities for innovative options.
Final Note: Lean adds value by reducing cycle time; Six Sigma adds value by eliminating defects.