Quality Function Deployment (QFD) is a means of eliciting user (customer) requirements (the “Voice of the Customer”) and turning them into system requirements in engineering language.

The QFD method was developed in Japan in the late 1960s by Professors Shigeru Mizuno and Yoji Akao of the Tokyo Institute of Technology. The Bridgestone Tire Company developed the first large scale application in 1966, using the initial, rather unweildy format based on fishbone analysis.

The House of Quality

The method soon moved on to using a matrix format, as it was found to be easier and better able to handle more complex situations. The rows represent customer needs or requirements and the columns are various functional requirements or quality characteristics, with the matrix indicating the strength of correlation (or lack of correlation) between the two.

Thus if one establishes what the customer’s requirements are, ideally by direct contact with the customer, rather asking your own engineers what they think the might be, they can then be related to design requirements.

The name “House of Quality” came about because the original rectangular matrix also has a triangular matrix on top of it, which looks like a roof and makes the whole diagram look like a house.

The house of quality first appeared in 1972 in the design of an oil tanker by Mitsubishi Heavy Industries, but became well known in the west due to the publication of a paper called  ‘The House of Quality’ by John R. Hauser & Don Clausing, Don in the Harvard Business Review in May 1988.

The House of Quality

4-Phase Model

To fully utilise the power of the QFD approach one can extend it to cover all four phases from customer requirements to production quality. Each of the four phases in a QFD process uses a matrix to translate the requirements from the previous phase into those for the next phase.

QFD - Four Phases

Modern QFD & ISO 16355

Whilst QFD is a very powerful method it can be very time consuming. Therefore in recent times attempts have been made to streamline it to make it more efficient, and this revised approach goes under a number of different names, such as Modern QFD, Quick QFD etc., depending upon which flavour you choose.

An ISO standard, ISO 16355 in eight parts, has been recently released, giving an up to date approach to QFD.

The Kano Model

The Kano model is a theory of product development and customer satisfaction developed in the 1980s by Professor Noriaki Kano, which classifies customer preferences into different categorise, as shown in the chart below.

Kano Model

Quality Function Deployment (QFD) makes use of the Kano model in terms of the structuring of the QFD matrices. It offers some insight into the product attributes which are perceived to be important to customers. Kano’s model focuses on differentiating product features, as opposed to focusing initially on customer needs.

If you would like to discuss how you might use QFD or other techniques in your NPD process, then please contact us.