Define Phase in Lean Six Sigma: Clarifying Problems and Customer Needs
What Is the Define Phase?
The Define phase is the critical starting point of any Lean Six Sigma improvement effort. It focuses on clearly identifying the problem, understanding customer requirements, and establishing the scope and objectives of the project.
A well-defined problem sets the direction for everything that follows. Without clarity at this stage, improvement efforts risk solving the wrong problem—or delivering results that don’t matter.
Why the Define Phase Matters
Many improvement initiatives fail not because of poor analysis or weak solutions—but because the problem was never clearly defined. The Define phase helps teams:
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Focus on the right problem
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Align with customer expectations (VOC)
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Establish clear goals and scope
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Avoid wasted time and effort downstream
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Build early stakeholder alignment and trust
Key Concepts in the Define Phase
This Knowledge Hub begins with the foundational ideas that underpin all Lean Six Sigma work:
🔹Voice of the Customer (VOC)
Understanding what customers truly need and expect.
🔹Problem Definition
Clearly articulating the issue in measurable, objective terms.
🔹Project Scope
Defining boundaries—what’s included and what’s not.
🔹Stakeholder Alignment
Ensuring everyone agrees on the problem and objectives.
🔹Critical to Quality (CTQ)
Translating customer needs into measurable requirements.
Common Tools Used in the Define Phase
The following tools are commonly used to structure and support the Define phase. Click on each topic to explore detailed explanations, examples, and practical applications.
🔹Problem Statement (5W2H)
Clearly defining the issue, impact, and scope
🔹Gemba Walk
Verify & validate problem through direct observation.
🔹SIPOC Map
A high-level view of the process (Suppliers, Inputs, Process, Outputs, Customers)
🔹CT Flow-Down (CT Tree)
Translating customer needs into measurable performance requirements
🔹Voice of Customer: Kano Analysis, Net Promoter Score
Interviews, surveys, focus groups, complaints analysis
🔹Project Charter
Documenting goals, scope, stakeholders, and success metrics
🔹Change Readiness Risk Assessment
Confirm that the conditions for a successful project exist.
🔹Stakeholder Analysis
Assess key stakeholders' level of support for the project
🔹Project Plan
Define project execution, including timelines, responsibilities, resources, and key deliverables.
Where Define Fits in the DMAIC Framework
The Define phase sets the foundation for all subsequent phases:
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Define – Identify the problem and customer requirements
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Measure – Understand current performance using data
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Analyze – Identify root causes of issues
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Improve – Implement solutions
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Control – Sustain the gains over time
👉 Explore each phase in detail by clicking on any of the following buttons
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