Critical to Quality Tree (CTQ Tree) is a method to define customer needs into specific, measurable, and actionable performance requirements. In other words, the Critical to Quality Tree (CTQ Tree) translates customer needs into quantified requirements for the product or service.

A Critical to Quality Tree (CTQ Tree) reflects what the consumers say are essential to success. It is best to determine the Critical to Quality parameters before starting any process improvements. Use a CTQ tree to investigate your customer base by moving from general needs to more specific ones.

CTQ Tree helps clarify what is considered a defect in the process and distinguish your client’s needs from their wants.

Identify the Voice of The Customer – Critical to Customer

The first step in creating a CTQ tree is to understand the voice of the customer. This requires learning what is important to the customer–surveys, interviews, Gemba Walks, and focus group analyses are a few tools and techniques used to understand the customer’s needs.

The next step is translating those requirements into measurable attributes of Critical to Client (CTC). Critical to Quality implies that customers have a certain quality threshold. Once a product meets that threshold, the product satisfies the customer’s requirements. For example, eCommerce sites such as Amazon know that customers generally require 2-day delivery or better for their products. That 2-day delivery window is Critical to the Customer figure.

CTC metrics may include both qualitative and quantitative data, as seen below.

One way of translating Voice of Client (VOC) to Critical to Client (CTC) is to view the needs identified and relate them to the Kano model.

Additionally, you could use quality function deployment (QFD) / House of Quality to relate the CTQs to the CTCs.

Now that we’ve stated Voice of Client in specific Critical to Client measures, it is time to figure out what our company needs to do to achieve those service levels. We do that by adding the analysis to the CTQ Tree.

Elements of the Critical to Quality Tree (CTQ) Tree

CTQ tree helps teams visualize the customers’ needs, drivers, and performance requirements. The tree starts by identifying the customer needs and then branches into drivers and further requirements.

• Need: The first step of the CTQ Tree is to identify the customer’s needs. This is the actual product or service that you deliver to the customer.
• Drivers: Once you determine the customer needs, identify the quality drivers that must be present to fulfill customer needs.
• Requirements: Finally, list the requirements for each driver. In other words, record measurable performance metrics for each driver.

When to use CTQ Tree

Six Sigma teams usually start with VoC data when defining a problem and identifying the goals for a project in the Define phase of DMAIC methodology. Once you have the VoC, create a CTQ tree to identify customer needs. It’s useful to build a CTQ tree to:

• Understanding the customer needs more clearly
• Identify current issues and improve the product or service
• Help design or develop a product or service during the early stages of the process
• Stand out from competitors

CTQ Tree Steps

• Identify the customers: Customer identification is crucial to the Voice Of Customer (VOC) process. A customer is a person or company that buys products or services.
• Solicit the Voice of the Customer: Soliciting the voice of the client is important for any organization. The best way to increase customer satisfaction is to ensure you deliver what they want when they engage with you.
• Understand customer needs: From the voice of the customer, understand the customer needs. You can also prioritize the customer inputs using Pareto analysis.
• Translate that data into Critical to Client measures. Then, set ranges and tolerances for the CTCs.
• Identify the quality drivers and determine how well your organization’s process needs to perform internally to meet those measures.
• Set parameters for your internal processes that deliver to those drivers- those are your Critical to Quality measures CTQs.
• Finally, validate the requirements with the customers

Critical to Quality Tree (CTQ) Tree Example

Example: A grocery store collected customer feedback to identify business improvement opportunities. From the data, they have realized that most customers are looking for an online option to place an order without being at the store to buy the groceries. Use the CTQ Tree method to translate customer needs into specific, measurable, and actionable performance requirements.

Benefits of the Critical to Quality Tree (CTQ) Tree

• CTQ Tree helps to identify the performance requirements to satisfy customers
• Focuses on the key metrics of customer satisfaction
• Translates customer requirements into CTQs
• Helps in quality improvement of product or service
• It helps designers understand the quality drivers of designing the product or service
• It is easy to visualize the customer needs, quality drivers, and requirements in a graphical way

Important Videos’ of CTQ Tree

ASQ Green Belt Critical to Quality Tree Questions

Question: Which of the following tools is used to translate broad requirements into specific requirements?

(A) A quality control plan
(B) The Theory of Constraints (TOC)
(C) A Critical to Quality (CTQ) tree
(D) A process flowchart

Answer:

A Critical to Quality tree. This is a definition question. A Critical to Quality tree takes the voice of the client and translates it into what your organization specifically has to do to meet those needs.

A process flowchart maps a process. A quality control plan can mitigate defects, ensure good quality, and avoid the costs of poor quality. The theory of constraints states that your process is limited by its weakest link.

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