Lean operates on the principles of removing wastes of any process, thus accelerating the velocity and reducing process costs.  It basically focuses on speed.  Six Sigma operates on the principles of reduction of variations and improvement of process yield.  It basically focuses on quality of any given service or product.  To have a competitive edge over others, you should effectively combine both Lean and Six Sigma tools and principles.  Their combination holds the perfect toolkit for addressing almost all types of process problems.

There are two important risks associated with Lean Six Sigma analysis. They are:

1.  Alpha Risk -  Alpha risk is defined as the risk of rejecting the null hypothesis when in fact, it is true.  This is the risk of stating that a difference exists, while actually there is no difference at all.  Alpha risk is also known as Type 1 error or Producers Risk.  It is expressed as a probability (for e.g., 0.05 or 5%).  The value 1-alpha indicates the confidence level of a given statistical test.  Thus if alpha level is 0.05, it means there is a 95% confidence level.

2.  Beta Risk -  Beta risk is defined as the risk of accepting the null hypothesis when in fact, the alternate hypothesis is true.  This is stating that no difference exists, while there is an actual difference.  Beta risk is also known as Type II Risk or Consumer Risk.  A statistical test should be able to detect differences which are important in your perspective.  Actually, beta risk is expressed as a probability (for e.g., 0.10 or 10%) that it will not detect differences.  An individual or organization can determine beta risk, which depends upon the nature of decision made.  In other words, it depends on magnitude of difference between the sample means, and it is managed by increasing the test sample size.  It is normal and acceptable to get a beta risk of 10% while making decisions.  The value 1-beta is called the “power” of a given statistical test.  This power is the probability of rejecting the null hypothesis, when it is indeed false.

These are the two major risks that need to be scrutinized while performing a Lean Six Sigma analysis.

Six Sigma is a proven methodology aimed to improve the measurable results for all types of organizations, including nonprofit, manufacturing, government, service, healthcare, and research organizations.  This methodology has to be introduced during the first phase of the deployment itself, so that improvement is obtained along with a generic problem-solving line of approach.  Six Sigma focuses on the leadership-sponsored projects.  DFSS (Design For Six Sigma) methodology deals with developing a new product or service that is defect-free.  Then there is the DMADV (Define-Measure-Analyze-Design-Verify) project methodology in Six Sigma.

Many people confuse the methodologies of Lean and Six Sigma.  Though there are many similarities, it is necessary to draw a comparison between Six Sigma and Lean, so as to understand Six Sigma better.

• Focus – The focus of Six Sigma is on reduction of variations and improvement of process yield by implementing a problem-solving approach.  Lean, on the other hand, focuses on optimization of the process flow and reduction of waste.
• Training – The entire process of Six Sigma training is broken down into five distinct phases of DMAIC (Define-Measure-Analyze-Improve-Control) process.  The time gap between each training session is utilized for application of tools that were learned previously.  On the other hand, Lean training is the combination of short training sessions on the principles and practical application on the shop floor.
• Duration – Six Sigma projects require duration of few months.  On the other hand, Lean projects could be completed in a couple of days.

The two well-known Six Sigma certifications are the Green Belt and the Black Belt.  And then you can go for the Master Black Belt Certification, which is the mastery over Six Sigma methodology.  The Six Sigma methodology could be used in combination with Lean to have a competitive edge over others.