House of Quality
This article provides a practical explanation of the concept of House of Quality, developed by Yoji Akao and Shigeru Mizuno. After reading, you will have a basic understanding of this powerful quality management tool.
What is the House of Quality?
The quality of products and/or services isn’t just important for businesses themselves, but especially for their customers. Customers decide what they think of a product/service. The better the quality in the opinion of the customers, the more likely that customers will have a positive response, come back, and recommend the product or service to others.
Still, it’s not easy to meet the quality standards that customers demand. The Quality Function Deployment (QFD) makes that possible. QFD is part of the Lean Six Sigma quality system.
It’s a method to inventory customer wishes and market demands and to then include these in the design brief. This method enables organisation to focus even more on what their customers want. The result of the QFD method is a data matrix, also called ‘the house of quality’. This house of quality can take on different shapes. In all cases, however, the representation will resemble a house.
The QFD method was invented in 1960 by Japanese planning expert Yoji Akao and Japanese quality expert Shigeru Mizuno.
The quality house is part of QFD and represents quality control. There’s also a focus on the execution of a quality plan and applying the resources to implement such a plan. Because quality functions are being established, it’s considered part of Lean Six Sigma. The quality house makes it easy to translate customer wishes and market demands into a design. In addition to function requirements, the functional specifications and technical design will also be considered. For instance, through the use of programme and system tests, it can be evaluated if the product meets the customers’ expectations.
The quality house is aimed at product development that has been inspired by customer wishes. In order to actually meet those wishes, it’s important to first carefully listen to the customers. All their ideas and wishes are translated into a realistic and feasible plan, looking at what is and isn’t possible based on priorities. This is a team process; all team members contribute and the process steps are taken several times. All the team members will have to listen to each other and ensure that quality is taken to a higher level and safeguarded. This entire process of converting customer wishes to design requirements generally follows the steps below:
1. Identify customer wishes
The first step is to find out what customers really want. That requires extensive research. Think of customer interviews, questionnaires, and collecting reviews. Complaints can also be a valuable source of information regarding what customers want exactly. Both existing customers and future customers can be useful sources of information. The goal of this phase is to get a better understanding of the customers’ wishes and to enable them to suggest their own ideal solution.
2. Relative importance
During this phase, you look at which customer wishes or requirements are considered the most important. This is indicated with ‘relative importance’. It involves assigning a score between 1 and 10, with 1 being least important, and 10 being most important. Interviews can be used to filter customer priorities. The value that a customer assigns to a certain specification or solution can also differ from what the manufacturer had in mind. For instance, a professional photographer might think that the quality of the lens and shutter time are more important than battery life.
3. User opinion
In addition to the above-mentioned research, the overall opinion of the user is also important. It can be obtained from competition research. By finding out what type of similar products competitors offer and what customers think of those, you can form a general impression. If the competitor offers certain extras or a slightly different modified product that users like, the manufacturer can do the same. With this information, they can adapt their own products and/or services.
Based on information that was obtained earlier, an organisation can determine a business strategy. Objectives, projected effort, and required resources will become clear, and a priority level can then be assigned to every adjustment, change, or addition. It’s important that different departments work towards the same goal; disagreements or misunderstandings between departments can undermine the expected results. The priorities have to be supported by all departments.
5. Product specifications
All available data will now have to be converted into specifications and/or design details. This means that the customer wishes have to be translated into technical specifications. The foundation of the quality house is being built.
6. Quality house
Now the relationship between wishes and specifications is plotted in a matrix (the quality house). It becomes clear to what extent these specifications will contribute to achieving the customer wishes. By recording specific requirements for how the product is realised, it becomes clear how to best meet customer demands. This is also where people can question why a certain method is chosen. Because all the requirements are written down, it should be easy to later determine whether an adjustment was successful.
In the quality house, specifications will now be compared and evaluated. The idea is to examine which aspects conflict and which strengthen each other, discovering the link between specifications. Eventually, this will lead to a logically feasible and traceable structure, which combines all (new) ideas.
Now it’s time to look at the relevance related to the specifications and/or design requirements. This is where the question is asked to what extent its feasible to make the adjustments.
9. Target values
The final step is to translate all the obtained results into design requirements and target values that will help to further improve the quality of the product and/or service.
Within the quality house, the focus during the design process is on customer wishes and/or customer requirements. However, developing and adapting physical products does require resources. Examples are employees, computers, machines, adjustment of machines, raw materials, and so on. It’s therefore important that all those means are facilitated by the organisation. By identifying which resources are available beforehand, it’s possible to respond more quickly to the additional resources that will be needed for the entire quality process.
Now it’s your turn
What do you think? Do you recognize the explanation of the House of Quality concept? What are your practical experiences with this methodology and do you see it as a valuable tool? Do you have any tips or additional comments?
Share your experience and knowledge in the comments box below.
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- Adiano, C., & Roth, A. V. (1994). Beyond the house of quality: dynamic QFD. Benchmarking for Quality Management & Technology, 1(1), 25-37.
- Akao, Y., & Mazur, G. H. (2003). The leading edge in QFD: past, present and future. International Journal of Quality & Reliability Management, 20(1), 20-35.
- Madu, C. N. (2006). House of Quality (QFD) in a Minute. Chi Publishers Inc.
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