Lean and Six Sigma are close cousins in the process improvement world and they have lot of commonalities. Now we will talk about the difference between Six Sigma and Lean Six Sigma.
Six Sigma uses a data centric analytical approach to problem solving and process improvements. That means, there would be time and effort in data collection and analysis. While this sounds very logical to any problem solving approach, there can be practical challenges.
For example, some times we may need data and analysis to be even prove the obvious. That is lame.
On the other hand, Lean Six Sigma brings in some of the principles of Lean. Lean is largely a pragmatic and prescriptive approach. Which implies that we will look at data and practically validate that problem and move on to prescriptive solutions.
Thus combining Lean with Six Sigma, helps in reducing the time and effort needed to analyze or improve a situation. Lean will bring in a set of solutions that are tried and tested for a situation. For example, if you have high inventory, that Lean would suggest you to implement Kanban.
Lean is appealing because most often it simplifies the situation and that may not be always true with Six Sigma. However the flip side to Lean is that if the system have been improved several times and reached a certain level of performance and consistency, Lean can bring out any further improvement unless we approach the problem with Six Sigma lens, using extensive data collection and analysis.
Looking at the body of knowledge of Six Sigma and Lean Six Sigma, you will find that Lean Six Sigma courses following tools: