How does parallel design work?

What is most striking about parallel design is how many ideas can be considered in a very short time. Most linear processes would only have considered a few iterations of a single design in the time that parallel design can consider many ideas. McGrew's design team considered at least 40 design alternatives in a single day. McGrew found that most participants responded immediately to good ideas. This was true even when good ideas were contained in otherwise poor design solutions.

Good user interface design requires designers first to "saturate the design space." This means that user interface designers should consider as many alternative design ideas as possible before selecting the best to take forward.