Learning from an unfinished design

Designers often build a simple model before producing a finished object. Such a model, known as a prototype, need not reproduce every feature of the proposed product. Its purpose is to make a particular question testable. A cardboard model of a desk, for instance, can reveal whether its height is comfortable even though it cannot support heavy equipment.

[A] Different questions require different models. [B] To investigate whether a desk can bear a large load, a designer needs materials with relevant structural properties. [C] A rough model that is excellent for one purpose may therefore be unsuitable for another. [D] Mistaking a model for a complete version of the final product can lead a team to draw conclusions its evidence does not support.

Simple prototypes also make revision less costly. When a team has invested heavily in a polished object, members may hesitate to change it, even after discovering a problem. A quickly constructed model can be easier to discard. The advantage is not that rough models always produce better ideas, but that they allow more ideas to be examined before a team commits substantial resources to one design.