About this lesson
Critical To Quality (CTQ)
Lean Six Sigma relies on the use of Critical to Quality (CTQ) characteristics. These are the attributes that will be used to measure success or failure of the project.
When to use
Every Lean Six Sigma project uses CTQs to express the internal and external customer needs that the project will attempt to address. These CTQs are developed in Define and Measure phases, then used throughout the project to measure project success.
CTQs are the technique used by Lean Six Sigma to express the project requirements. They are derived from the internal and external customer needs. The external customer is normally a buyer or end user of a product or service but does also include agencies that may levy requirements on a project such as regulatory bodies or government agencies. The internal customers are usually considered in two categories. One is the internal business function or unit that is using the result of a business process, such as the payroll process. These are often called operational CTQs. The other category includes CTQs that are associated with following the Lean Six Sigma project management methodology or project boundary constraints directed by the project stakeholders. These could include requirements for how one DMAIC phase of the project is completed and the next phase started.
When developing CTQs, follow this process:
- Start with one of the product or process functions or features.
- Identify what the customer wants that function or feature to accomplish for them.
- Often the initial description of what the customer wants is vague or general, so ask “What does that mean” to get a more specific understanding of the customer need.
- Continue asking “What does that mean?” until you have an actionable and measurable need.
- Write the CTQ in the format: “The product/process function” performs “the customer need” in this “measurable manner.”
Hints & tips
- CTQs should have a measurable component based upon an objective standard (not a feeling).
- In the Define phase you will often have high-level CTQs. In the Measure phase those are frequently deployed down to specific product features or process steps and become much more specific.
- When closing out a Lean Six Sigma project, always go back to the original high-level CTQs and demonstrate how the results of the project relate to those CTQs.
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