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Quality Function Deployment (QFD)

Quality Function Deployment (QFD) is a technique introduced in Japan by Yoji Akao in 1966 and used extensively by Toyota (and since by many other companies around the globe).

The technique aims to capture what the customer needs, and work to how it might be achieved. According to Akao (1990), QFD "is a method for developing a design quality aimed at satisfying the consumer and then translating the consumer's demand into design targets and major quality assurance points to be used throughout the production phase".

It is a structured procedure used to translate the expressed or perceived needs of customers first into specific product or service design characteristics and features, and then into process and operational characteristics. In this translation it attempts to prioritise the requirements of the design process (the 'what's) and reconcile them with the attributes embodied in the design solution (the 'how's) - using a specific mechanism known as the "what-how" matrix.

First, customers' requirements, which form the vertical axis of the matrix, are matched with the design attributes which form the horizontal axis of the matrix. The individual elements of the matrix are used to indicate the degree and direction of influence of the main design attributes on customer needs. To do this some kind of coding scheme is used. This is often pictorial using, for example, circles and triangles. It is important at this stage to clearly record all assumptions used in judging the nature of these relationships. The purpose is to make explicit what, without QFD, might have remained unexplained in the design process.

The correlation between different design attributes is recorded so that the consequence for other attributes of changing one attribute is understood. In addition, specific target values of each design attribute may be defined and, if the product or service is already in use, a competitive assessment comparing the product or service in question with competitors' offerings may be mapped.

Similarly, a perceived customer rating of each requirement comparing current product or service performance against competitors can also be recorded.

Once the important design attributes have been identified together with an understanding of their current state, they can be transposed to a second matrix to form the "what"s. These must be reconciled with the specific design features of the product or service.

After a similar analysis these in turn form the "what"s of the process matrix which links the design features of the product or service with the attributes of the design of the process which will create the product or service. This in turn may be extended by a final operational matrix to help design the operational control system used in the process.

QFD requires designers to be both analytical and explicit in terms of their design objectives ("what"s), their design solutions ("how"s) and the relationship between them. It also helps to integrate the various functions and departments commonly associated with design activities in large organisations.

A disadvantage cited by practitioners is the complexity involved in using QFD in large design projects; the number of factors used in each axis of the matrix must be minimised if the process is not to become unmanageable. Conversely, if the number is artificially restricted too severely, important relationships may be overlooked.

See Akao, Y., ed. (1990). Quality Function Deployment, Productivity Press, Cambridge MA

See also the International Council for QFD

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