Lean Six Sigma: Elements of ANALYZE

The third Phase in the 6 Sigma DMAIC methodology is Analyze. Previously, we discussed the steps in the DMAIC Define Phase and Measure Phase. In the Define Phase, the focus is on agreement of what the problem is, it’s impact on customers, the firm, and with initial quantification of the “pain.” In the DMAIC Measure Phase of 6 Sigmas, the focus is on data collection, to validate that what was thought of as a problem truly is a problem. In the DMAIC Analyze Phase, the focus turns to identifying the root causes for the problems the firm, the customer, and the employees experience.

Below is a general roadmap of items to remember and satisfy in the DMAIC methodology of Six Sigma in the Analyze Phase.

DMAIC: Analyze Phase Storyboard

Visually,

Lean Six Sigma: Goals for Analyze Phase

The Analyze Phase in 6 Sigma is designed to accomplish the following:

• Use data to help focus the team on finding and verifying the true root causes of problems
• Specific objectives for ANALYZE include: Perform Cause and Effect analysis on the problem
• Continue analysis to the level of actionable root causes
• Select the root causes with the greatest impact to improve the CTQ
• Verify the root causes with data using the appropriate tools and display the analysis and techniques used
• Verified Root Causes will form the foundation for solutions in the Improve Phase failing to find true root causes will cause you to take actions on the wrong things and miss the targeted improvement

The DMAIC storyboard for the Analyze Phase above outlines the steps for us:

1. Root Cause Analysis
2. Identify Root Causes
3. Create Test Plan to test each Root Cause (a Root Cause is also a Hypothesis)
4. Test Hypothesis (Test Root Causes) using statistical hypothesis testing
5. Tollgate to the DMAIC Steering Committee

Some Common Tools used in the DMAIC Analyze Phase are:

• Affinity Diagram
• Digraph
• Root Cause Analysis, Fishbone Diagram / Ishikawa Diagram, Cause and Effect Diagram

When root causes are identified, we can consider those to be Hypothesis, which need to be validated or invalidated as true root causes. To verify our hypothesis, a few statistical tools are used:

• Scatter Plot or Regression Analysis
• Present / Not Present Matrix, Contingency Table (Chi Square Analysis)
• And other methods of hypothesis testing (not covered in this post)

Once a root cause is verified as a true root cause, then that paves the way for the Improve Phase in DMAIC, where we focus on practical solutions that will surgically attack the root causes we validated in the Analyze Phase.