Thinking about how Six Sigma and Lean Manufacturing work well together despite being distinct, independent and complete tools? The combined principles gel so well that they compliment each other and progress parallels to each other on a well-defined path. The paths are defined by the 5 Laws of Lean Six Sigma as we know today.

5 Laws of Lean Six Sigma

The 5 laws have been formulated in order that efforts on improving quality and business process aimed at improving customer satisfaction and ROI as primary concerns. The 5 laws have evolved over time and are a collection of key ideas derived both from Lean Manufacturing and Six Sigma.

1.      The Zeroth Law: The first law is called so because all other principles are built upon this fundamental one. It States that “The Law of the Market - Customer Critical to Quality defines quality and is the highest priority for improvement, followed by ROI (Return on Investment) and Net Present value.”

2.      The First Law: This is called as The Law of Flexibility. It states that “The velocity of any process is proportional to the flexibility of the process.” Interpretation: the more the process is receptive and flexible to adopt changes, the better the progress of the project implementation is.

3.      The Second Law: The second law is known as The Law of Focus - it is defined as “20% of the activities in a process cause 80% of the delay.” This can be interpreted as main causes of delay of activities originating from just 20% of activities thus enables a faster refocus during the reorientation phase.

4.      The Third Law: The Law of Velocity as the third law is known is stated as “The velocity of any process is inversely proportional to the amount of WIP. This is also called "Little's Law". This explains how the inertia of WIP, ‘Work in Progress’, bears heavily on the velocity of project implementation. Higher the number of works in progress (read unfinished tasks) the lower is the speed of progress due to various ground level handicaps

5.      The Fourth Law: The Fourth Law, which is the last of the 5 laws of lean Six Sigma, is defined as “The complexity of the service or product offering adds more non-value, costs and WIP than either poor quality (low Sigma) or slow speed (un-Lean) process problems.” The bulky nature of products is against the foundation of Lean Manufacturing principles. The bulk, complex manufacturing process and product and service specifications contributes to render the offerings redundant. As an illustration to this 4^th Law of lean Six Sigma, you can try and reason out why passenger cars are more and more becoming driver friendly despite their complex engineering features and functions.

You can revisit the definitions of Six Sigma and Lean Manufacturing principles which emphasize eliminating process errors and variations.  It also concentrates on efforts to invest less human labor, inventory, and time for product development.