Anticlue

Critical-to-Quality Tree

The Critical-to-Quality Tree or CTQ Tree is the six sigma tool for transforming customer requirements into measurable data. The CTQ Tree identifies and describes customer requirements in a specific measurable manner. Once specific Critical to Quality requirements have been obtained, products or service measurements can be compared to them quantitatively.

The advantages of using a CTQ Tree are:

• translating vague or broad customer needs into specific requirements
• helping Sigma teams move from general to detailed specifications
• ensuring that all aspects of the customer requirement are identified.

The steps to create and use a Critical-to-Quality Tree are:

1. Identify the key customer requirement - In step 1, the team identifies the key requirement the customers have for the product or service. This is done through open discussion. Usually, this requirement is expressed in the broadest possible terms, such as good customer service, to ensure the team does not miss anything.
2. Identify the customer's first tier of requirements - In step 2, the team identifies two or three requirements that resolve the key customer need identified in step 1. Good customer service might mean that the phones are answered quickly by knowledgeable staff.
3. Identify the customer's second tier of requirements - In step 3, the team identifies two or three requirements that further resolve each of the customer requirements identified in step 2. Phones answered quickly might be defined as within 2 rings. A knowledgable staff might related to staff being able to answer 90% of the calls before transferring to another individual.
4. Stop when quantifiable requirements are reached - Step 4 is applied when the team reaches a requirement that can be measured. The team would stop identifying requirements if the requirements are distinctly measurable.
5. Confirm your final requirements with your customers - Step 5 is applied after all the requirements on the CTQ Tree have been defined to a quantifiable degree. Each requirement should be confirmed with the customers.

The CTQ Tree is not the final step in a product or service improvement project. Instead, the tree serves as a good way to determine which improvements need to be made. In that light, the CTQ Tree is just the beginning. It yields a measurable base to compare the service or product to that standard, so a indication can be observed.