6. Design Freedoms

A key element of the product definition is the setting of clear limits on the design freedoms of the designer. Those involved in product definition will understand the dangers of both over definition and under definition. It is all too easy to specify a requirement in such a way as to assume a particular implementation. On the other hand it is all too easy to specify a requirement so generally that the designer needs to commit to large scale research activities to identify and choose a development path.

Over Definition

The problem of over definition occurs when the product requirements are based on a key technology or a specific method of implementation rather than a market requirement. All requirements need to be tested for motive. The key motives will include market based requirements but also a number of business or business mission related requirements. For example, it may be appropriate to specify a particular aspect of a product in order to make use of surplus stocks, a manufacturing technology or competence.

To test each specified requirement for motive is probably the most effective method of testing the validity of a product definition's contents. A motive that is unsupported by market requirement, business requirement or other bona fide requirement should be reviewed to determine whether the requirement is impinging on design freedom.

Over definition is difficult to avoid and designers working from a product definition should be encouraged to question any perceived occurrence of that nature. The evolution of new techniques, processes or ways of thinking can change the perception of a product definition over time.