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.