Quality Function Deployment (QFD) is a method of translating qualitative customer demands into coordinated process planning with quantitative outcomes. Mitsubishi introduced it in the early 70s, and it became associated with the more robust TPS and TQM methodologies.
Amplifies the “voice of the customer”
Used for quality assurance, processing planning in value engineering
Developed by Mitsubishi in the 1970s for shipbuilding requirements
Known as QFD, and is cohesive with TQM
Matrix called “house of quality”
It first appeared in a plan blueprint for Mitsubishi Heavy Industries in 1972, which was the head center for electronic engineering in Tokyo. The House of Quality matrix iconic to QFD helped organize all the strategic goals and limitations of shipbuilding.
It was such a complicated process, with so many strict requirements by which to abide, that being able to visually plot the goals in opposition to each other was extraordinarily helpful. Quality Function Deployment became more popular, and was adopted by Toyota in its pursuit of the Toyota Production System, and then at Ford Motors in North America.
Today, it is a high-value tool for quality manufacturing that enables strategic leadership planning at the executive level.
The main tool used in quality function deployment is the “house of quality,” a decision matrix that visually displays all the customer issues for the project at hand.
Here is an example of a house of quality matrix used for QFD:
Image from Wikipedia entry for Quality Function Deployment, titled “A house of quality for enterprise product development processes: House of Quality is a diagram, resembling a house, used for defining the relationship between customer desires and the firm/product capabilities”
You may think it looks very complicated, and it is – one of the major critiques of QFD is the level of detail and complexity in matrix visualization. That same complexity, however, allows for decision makers to see convoluted areas in the planning stage and adjust as necessary.
So, alternatively, why are there so many tiny details in houses of quality?
Because it’s not just what you can do for the customer, it’s what the customer wants and how they see the balancing of all their desired outcomes. Hence, the "voice of the customer".
Think of the house of quality like a literal house, with a foundation, walls, roof, and accessible rooms. If the foundation is weak, or doesn’t allow for the required space to build other elements, then the entire structure won’t last long before it crumbles. Similarly, if there is a part of the construction that is compromised, like a leaky roof due to lack of funds/planning/resources, then the other “rooms” of the house will be negatively affected.
The House of Quality emphasizes the project as a working whole unit, with parts that continually influence each other when changes are deployed.
Robin Kent, in Quality Management in Plastics Processing, gives a helpful (and slightly easier) visual for a QFD matrix room by room:
Quality Function Deployment – and particularly the House of Quality matrix – is a valuable tool in the lean manufacturing toolkit precisely because it covers so many aspects of a production process, from design, marketing, quality, production, and sales, to distribution.
Beware that it is not beginner-friendly, nor should it necessarily be the first tool that should be utilized (choose something more simple like a DFMEA approach in the planning and roadmap stages) but it can definitely be helpful balancing a project’s paradoxical goals and standards that may initially appear to be at odds.
Used in tandem with other process planning tools in Total Quality Management and Six Sigma methodologies, the House of Quality will help your project stand strong.