What is Critical to Quality Tree

Guide: Critical to Quality (CTQ)

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Author: Daniel Croft

Daniel Croft is an experienced continuous improvement manager with a Lean Six Sigma Black Belt and a Bachelor's degree in Business Management. With more than ten years of experience applying his skills across various industries, Daniel specializes in optimizing processes and improving efficiency. His approach combines practical experience with a deep understanding of business fundamentals to drive meaningful change.

Guide: Critical to Quality (CTQ)

Critical to Quality (CTQ) is a fundamental concept in continuous improvement and quality management, particularly within Six Sigma and other similar methodologies. It focuses on understanding and defining the essential characteristics or requirements of a product or service that are vital to meet or exceed customer needs.

Rooted in the Voice of the Customer (VOC), CTQ involves capturing both explicit and implicit customer needs and expectations. The process of identifying CTQs is strategic, aiming to align product or service development with customer expectations, thus fostering enhanced satisfaction and loyalty. This alignment is crucial in building trust and reliability between the customer and the brand, as it ensures that products or services precisely resonate with customer needs.

What is Critical to Quality

Critical to Quality is a common method used in continuous improvement and quality management, particularly within Six Sigma activities and other quality-focused methodologies. Central to CTQ is understanding the characteristics or requirements of a product or service necessary to meet or exceed the customer’s needs. CTQs come from what is known as the Voice of the Customer (VOC), which is a term that is used to understand all the needs and requirements of the customer, both stated and unstated.

Identifying CTQs is not just a tick-box exercise; it is a strategic approach that should be taken to align the development of products or services with the expectations of the customers (their voice). This alignment is important if you want to enhance customer satisfaction and develop customer loyalty. This is important, as when a product or service resonates with the specific needs and expectations of the customer, this creates trust and reliability between the customer and the brand.

The importance of CTQs

CTQS is the method that connects and translates intangible customer expectations into tangible and measurable product or service specifications.

For example, in a coffee shop, customers frequently complain about long wait times. To address this, the shop translates this intangible expectation of “faster service” into a tangible Critical to Quality (CTQ) measure: “Customers should receive their coffee within 3 minutes of ordering.” This clear, measurable goal allows the shop to adjust its processes and staffing to ensure quicker service, directly addressing the customers’ primary concerns and enhancing overall satisfaction.

This translation is an important process. It involves converting customer needs, which can often be broad and ambiguous, into clear, objective, and quantifiable criteria.

Identifying CTQs

Identifying CTQ factors starts with a deep understanding of customer needs; these are usually gathered via surveys, interviews, focus groups, or direct feedback. This crucial step involves converting customer requirements, often vague or broad, into specific, measurable, and actionable quality specifications. By doing this, businesses can translate abstract customer expectations into clear, quantifiable criteria, ensuring that products or services are designed and refined to meet these defined standards, thereby aligning closely with customer expectations.

Developing a CTQ Tree

Step 1: Capture the Voice of the Customer

The first step in developing CTQs is capturing the voice of the customer. This is about understanding what the customer truly values from the product or service you are looking to offer. The VOC is the customer’s expectation, so we need to capture this from the customers by using methods such as surveys, interviews, and collecting direct customer feedback.

These should be structured with questions that can identify customers’ expectations, preferences, and experiences with a product or service.

Example: A coffee shop wants to improve customer satisfaction. They conduct surveys, gather feedback through comment cards, and interview regular customers.

Action: They ask questions like, “What do you value most in your coffee experience?” or “What improvements can we make to enhance your visit?” From this, they learn that customers care about the quality of the coffee, the speed of service, and the ambiance of the shop.

Step 2: Identify the Critical Needs

Once you have collected the VOC, the next step is to sort through the customer feedback and group feedback by themes or affinity to create categories of focus. At this stage, you will typically find that the customer’s expectations are generally broad and unmeasurable. However, identifying these needs is important and will form the foundation for developing specific quality requirements. 

Example: The coffee shop analyzes the collected feedback and identifies recurring themes.

Action: They notice that customers frequently mention the desire for quicker service, especially during rush hours, the consistent taste of coffee, and a comfortable seating area. These become the broad categories of focus.

Step 3: Breakdown the Needs into CTQs

These critical needs from the VOC then need to be broken down into more specific requirements, known as Critical to Quality (CTQ) requirements. This step involves a detailed analysis to translate general customers’ needs into explicit, measurable, and actionable quality criteria.

Example: The coffee shop needs to translate these broad needs into specific quality requirements.

Action: For the need for quicker service, a potential CTQ could be “reducing the average wait time to under 3 minutes.” For consistent taste, a CTQ might be “implementing a standard recipe for each type of coffee.” For ambiance, a CTQ could be “ensuring seating comfort and availability.”

Step 4: Develop the CTQ Tree

The next step is to develop a critical-to-quality (CTQ) tree. This involves placing the customer’s needs as the trunk of the tree, with the branches of the trunk representing specific and measurable CTQs. This tree structure is useful to visually see how broad customer needs are connected to detailed quality requirements. This process helps stakeholders understand the collection and relationship between what customers want and the specific quality attributes that need to be achieved (KPIs)

Example: The coffee shop creates a visual representation linking customer needs to specific CTQs.

Action: The tree’s trunk represents the broad needs: service speed, taste consistency, and ambiance. Branching out from these are the CTQs: average wait time, standard coffee recipes, and seating comfort. This helps visualize how each specific quality requirement stems from a core customer need.

Step 5: Define Performance Standards for Each CTQ

Finally, for every CTQ that is identified, performance standards or specifications should be created. These will be metrics that are quantifiable and set clear benchmarks for quality. They will define the level of performance that must be achieved to meet the customer’s expectations. Setting these standards is important, as they provide specific targets for product development, quality control, and continuous improvement efforts.

Example: The coffee shop sets measurable goals for each CTQ.

Action: For the CTQ of reducing wait time, the standard could be “95% of orders fulfilled in under 3 minutes.” For taste consistency, a standard might be “100% adherence to coffee brewing procedures.” For ambience, a goal could be “availability of seating 90% of the time during peak hours.”

This is the process for understanding customers’ needs. Following this, constant data collection will be needed to measure how well those needs are being met. Actions and continuous improvement is then needed to be deployed to ensure customers’ needs are met or even exceeded.

Implementing CTQs in Quality Management

Once CTQ factors have been identified and defined, it is important to integrate them into the existing quality management framework. This involves establishing systems and procedures that are designed to monitor and control these CTQs.

Step 1: Set Up Monitoring Systems

You may need to adapt or develop your monitoring systems to collect information and keep track of CTQs and the results vs customer expectations. This can involve setting up metrics in quality and monitoring software, implementing or modifying production line checks, or implementing new customer feedback channels.

Step 2: Creating Procedures for Control

Procedures then need to be defined that dictate how to respond when a CTQ standard is not met. These can include Response or Control Plans which state what action needs to be taken by who

Step 3: Regular Measurement and Analysis

Once the control plans are in place, regular measurements of CTQs are needed to ensure that the product or service consistently meets the established quality standards. This involves not just collecting data but also analyzing it to identify trends, potential problems, or areas for improvement.

Step 4: Feedback Mechanisms

Finally, it is important to establish methods for customers to provide ongoing feedback. This continuous loop of feedback ensures that the product or service CTQs remain relevant and can be adjusted to reflect the changing customer needs or market conditions. 


The implementation of Critical to Quality (CTQ) in quality management is a robust process that transforms customer expectations into measurable and actionable quality standards. It begins with capturing the Voice of the Customer, identifying critical needs, and breaking these down into specific CTQs.

Developing a CTQ Tree visually links broad customer needs to detailed quality requirements, helping stakeholders understand and meet key performance indicators. Finally, setting performance standards for each CTQ and continuously monitoring and adjusting them ensures that products or services consistently meet customer expectations. This comprehensive approach not only enhances customer satisfaction but also drives continuous improvement, leading to sustained business excellence and customer-centric growth.


A: Critical to Quality (CTQ) is a term used in the field of Six Sigma and quality management. It refers to the key measurable characteristics of a product, process, or service that directly affect customer satisfaction. CTQs are the specific attributes or specifications that need to be met to ensure high-quality deliverables.

A: Understanding CTQ is crucial because it allows organizations to focus on the aspects that truly matter to customers. By identifying and measuring the critical quality characteristics, businesses can prioritize their efforts and resources to improve those areas. This helps in achieving customer satisfaction, reducing defects, and enhancing overall product or service quality.

A: Determining CTQs involves a systematic analysis of customer requirements, expectations, and feedback. This can be done through methods like surveys, interviews, focus groups, or data analysis. By understanding customer needs, translating them into specific metrics, and aligning them with business goals, organizations can identify the CTQs that should be targeted for improvement.

A: CTQs can vary depending on the industry and the specific product or service. Some examples of CTQs include product dimensions, durability, reliability, response time, speed, accuracy, error rates, customer support responsiveness, delivery time, and cost. The key is to identify the characteristics that have a direct impact on customer satisfaction and align them with business objectives.

A: CTQs can be measured using various statistical and analytical methods. This may involve collecting and analyzing data related to the critical quality characteristics. Statistical tools like control charts, capability analysis, process capability indices, and customer satisfaction surveys can be used to assess and quantify the performance of CTQs.

A: CTQs are a fundamental concept within the Six Sigma methodology. Six Sigma aims to minimize defects and improve quality by reducing process variability. CTQs help in identifying the key characteristics that need improvement, and Six Sigma provides a structured approach to achieve this improvement by using statistical analysis and process improvement techniques.

A: Yes, CTQs can change over time as customer preferences, market dynamics, and business goals evolve. It is important for organizations to regularly reassess and update their understanding of CTQs to stay aligned with customer expectations and remain competitive in the market.

A: Organizations can use CTQs to drive improvement by setting targets or goals for each critical quality characteristic. By monitoring and measuring the performance of these CTQs, organizations can identify areas of improvement and take corrective actions. Continuous monitoring and improvement of CTQs help in achieving higher levels of customer satisfaction and delivering high-quality products or services.


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Daniel Croft

Daniel Croft is a seasoned continuous improvement manager with a Black Belt in Lean Six Sigma. With over 10 years of real-world application experience across diverse sectors, Daniel has a passion for optimizing processes and fostering a culture of efficiency. He's not just a practitioner but also an avid learner, constantly seeking to expand his knowledge. Outside of his professional life, Daniel has a keen Investing, statistics and knowledge-sharing, which led him to create the website www.learnleansigma.com, a platform dedicated to Lean Six Sigma and process improvement insights.

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