Identify Root Causes

To correctly identify a root cause, a complete understanding of the process is necessary. This does not mean just understanding how a process was designed to work. It means understanding how the process is actually working. To accomplish this you need to:

Have clearly defined goals for data collection
Identify the data that needs to be collected
Have a defined reason for the data being collected
Establish what insights are expected from the data
Ensure accurate communication by clearly defining terms
Ensure that measurements are accurate and repeatable
Establish a standardized data collection system/process

Sample Problem

Eliminate Variation

six sigma principles eliminate variation

After identifying root causes, make changes to the process that will eliminate variation, and thus eliminate defects from the process. Also look for ways to eliminate steps that do not add value for the customer. This will eliminate waste.

Be proactive in identifying variation and eliminating it. Don’t wait for signs of variation to become obvious. Collect data, talk with people, and study the data to find variations in the process that may have become accepted because “that’s the way we’ve always done things.”


Define the problem and desired outcome:
Define Customers and Requirements (CTQs) / Develop Problem Statement, Goals and Benefits / Identify Champion, Process Owner and Team / Define Resources
Evaluate Key Organizational Support / Develop Project Plan and Milestones
Develop High Level Process Map
Measure the ability of the process:
Define Defect, Opportunity, Unit and Metrics / Detailed Process Map of Appropriate Areas / Develop Data Collection Plan / Validate the Measurement System
Collect the Data / Begin Developing Y=f(x) Relationship
Determine Process Capability and Sigma Baseline
Analyze the data and identify the root cause of variations (defects):
Define Performance Objectives / Identify Value/Non-Value Added Process Steps
Identify Sources of Variation / Determine Root Cause(s)
Determine Vital Few x’s, Y=f(x) Relationship
Improve or modify the process so that fewer variations (defects) are produced:
Perform Design of Experiments / Develop Potential Solutions
Define Operating Tolerances of Potential System / Assess Failure Modes of Potential Solutions / Validate Potential Improvement by Pilot Studies
Correct/Re-Evaluate Potential Solution
Control the process. Prevent and correct variations before they result in defects:
Define and Validate Monitoring and Control System / Develop Standards and Procedures
Implement Statistical Process Control / Determine Process Capability
Develop Transfer Plan, Handoff to Process Owner
Verify Benefits, Cost Savings/Avoidance, Profit Growth
Close Project, Finalize Documentation
Communicate to Business, Celebrate

About The Author

Math Expert/Six Sigma Black Belt/Management Expert
I have tutored 3rd-7th grade students in Math, Science and Social Studies at my local church, and have also tutored adults with Seeds of Literacy in Cleveland Ohio that were working towards there GED. I have over 20 years experience in Management and Excel,Word,PowerPoint and I am very analytical.
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