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Chapter 5 The design of products and services 127
Figure 5.8 QFD matrices can be linked with the ‘hows’ of one matrix forming the ‘whats’ of the next
● The central matrix (sometimes called the ‘relationship matrix’) represents a view of the
interrelationship between the whats and the hows. This is often based on value judgements
made by the design team. The symbols indicate the strength of the relationship – for
example, the relationship between the ability to link remotely to the system and the intranet
compatibility of the product is strong. All the relationships are studied, but in many cases,
where the cell of the matrix is blank, there is none.
● The bottom box of the matrix is a technical assessment of the product. This contains the
absolute importance of each design characteristic. [For example, the design characteristic
‘interfaces’ has a relative importance of (9 × 5) + (1 × 9) = 54.] This is also translated into
a ranked relative importance. In addition, the degree of technical difficulty to achieve high
levels of performance in each design characteristic is indicated on a 1 to 5 scale.
● The triangular ‘roof ’ of the ‘house’ captures any information the team has about the
correlations (positive or negative) between the various design characteristics.
Although the details of QFD may vary between its different variants, the principle is generally
common, namely to identify the customer requirements for a product or service (together with
their relative importance) and to relate them to the design characteristics which translate those
requirements into practice. In fact, this principle can be continued by making the hows from
one stage become the whats of the next (see Fig. 5.8). Some experienced users of QFD have
up to four linked matrices in this way. If engineering or process trade-offs need to be made at
a later stage, the interrelated houses enable the effect on customer requirements to be determined.
Value engineering
Value engineering
The purpose of value engineering is to try to reduce costs, and prevent any unnecessary
costs, before producing the product or service. Simply put, it tries to eliminate any costs that
do not contribute to the value and performance of the product or service. (‘Value analysis’
is the name given to the same process when it is concerned with cost reduction after the
product or service has been introduced.) Value-engineering programmes are usually conducted
by project teams consisting of designers, purchasing specialists, operations managers
and financial analysts. The chosen elements of the package are subject to rigorous scrutiny,
by analysing their function and cost, then trying to find any similar components that could
do the same job at lower cost. The team may attempt to reduce the number of components,