In the world of business and industry, every organization has customers. Some have only internal customers, some just external customers, and some have both. When you are working to determine what you need to accomplish to satisfy or even delight your customers, then the tool of choice is quality function deployment or QFD.
QFD is a structured approach to defining customer needs or requirements and translating them into specific plans to produce products to meet those needs. The “voice of the customer” (VOC) is the term to describe these stated and unstated customer needs or requirements.
Quality professionals refer to QFD by many names, including matrix product planning, decision matrices, and customer-driven engineering. Whatever you call it, QFD is a focused methodology for carefully listening to the voice of the customer and then effectively responding to those needs and expectations.
First developed in Japan in the late 1960s as a form of cause-and-effect analysis, QFD was brought to the United States in the early 1980s. It gained its early popularity as a result of numerous successes in the automotive industry.
In QFD, quality is a measure of customer satisfaction with a product or a service. QFD is a structured method that uses the seven management and planning tools to identify and prioritize customers’ expectations quickly and effectively.
Beginning with the initial matrix, commonly termed the house of quality, depicted in Figure 1, the QFD methodology focuses on the most important product or service attributes or qualities. These are composed of customer wows, wants, and musts. (See the Kano model of customer perception versus customer reality.)
Once you have prioritized the attributes and qualities, QFD deploys them to the appropriate organizational function for action, as shown in Figure 2. Thus, QFD is the deployment of customer-driven qualities to the responsible functions of an organization.
House of Quality Processes
Step 1: Customer Requirements – “Voice of the Customer (VOC)”
The first step in a QFD project is to determine what market segments will be analyzed during the process and to identify who the customers are. The team then gathers information from customers on the requirements they have for the product or service. In order to organize and evaluate this data, the team uses simple quality tools like Affinity Diagrams or Tree Diagrams.
Step 2: Regulatory Requirements
Not all product or service requirements are known to the customer, so the team must document requirements that are dictated by management or regulatory standards that the product must adhere to.
Step 3: Customer Importance Ratings
On a scale from 1 – 5, customers then rate the importance of each requirement. This number will be used later in the relationship matrix.
Step 4: Customer Rating of the Competition
Understanding how customers rate the competition can be a tremendous competitive advantage. In this step of the QFD process, it is also a good idea to ask customers how your product or service rates in relation to the competition. There is remodeling that can take place in this part of the House of Quality. Additional rooms that identify sales opportunities, goals for continuous improvement, customer complaints, etc., can be added
Step 5: Technical Descriptors – “Voice of the Engineer”
The technical descriptors are attributes about the product or service that can be measured and benchmarked against the competition. Technical descriptors may exist that your organization is already using to determine product specification, however new measurements can be created to ensure that your product is meeting customer needs.
Step 6: Direction of Improvement
As the team defines the technical descriptors, a determination must be made as to the direction of movement for each descriptor.
Step 7: Relationship Matrix
The relationship matrix is where the team determines the relationship between customer needs and the company’s ability to meet those needs. The team asks the question, “what is the strength of the relationship between the technical descriptors and the customers needs?” Relationships can either be weak, moderate, or strong and carry a numeric value of 1, 3 or 9.
Step 8: Organizational Difficulty
Rate the design attributes in terms of organizational difficulty. It is very possible that some attributes are in direct conflict. Increasing the number of sizes may be in conflict with the companies stock holding policies, for example.
Step 9:Technical Analysis of Competitor Products
To better understand the competition, engineering then conducts a comparison of competitor technical descriptors. This process involves reverse engineering competitor products to determine specific values for competitor technical descriptors.
Step 10: Target Values for Technical Descriptors
At this stage in the process, the QFD team begins to establish target values for each
technical descriptor. Target values represent “how much” for the technical descriptors, and can then act as a baseline to compare against.
Step 11: Correlation Matrix
This room in the matrix is where the term House of Quality comes from because it makes the matrix look like a house with a roof. The correlation matrix is probably the least used room in the House of Quality; however, this room is a big help to the design engineers in the next phase of a comprehensive QFD project. Team members must examine how each of the technical descriptors impact each other. The team should document strong negative relationships between technical descriptors and work to eliminate physical contradictions.
Step 12: Absolute Importance
Finally, the team calculates the absolute importance for each technical descriptor. This numerical calculation is the product of the cell value and the customer importance rating. Numbers are then added up in their respective columns to determine the importance for each technical descriptor. Now you know which technical aspects of your product matters the most to your customer!
From VOC, to Engineering, Process, and Quality Prescriptions
Translating the Voice-Of-The-Customers to the necessary prescriptions to guide the downstream-players of the organization, requires building four more HOQs similar to the initial Requirements Matrix i.e., (see also Figure 2 below)
- Design Matrix,
- Product Characteristics Matrix,
- Manufacturing/ Purchasing Matrix,
- Quality Control/ Verification Matrix.
Benefits of Using QFD
There are several benefits to using QFD. Besides requiring fewer resources than other quality tools, it can:
- Improve a company’s processes, products or services.
- Produce a faster outcome than other methods can.
- Give definition to the design process.
- Help a team stay focused.
- Allow for easy management and peer review of design activities.
- Help present the information graphically.
- Leave the team well positioned in case it needs to improve upon its results for future processes, products or services.
Many QFD practitioners claim that using QFD has enabled them to reduce their product and service development cycle times by as much as 75 percent with equally impressive improvements in measured customer satisfaction.
- Jack B. ReVelle’s Quality Essentials: A Reference Guide from A to Z, ASQ Quality Press, 2004.