Why to fail?

People think that all is necessary is to determine the requirements, then built to those requirements. Test, they believe, are only necessary to ensure that the requirements are met. This lead to so many unusable systems. Deliberate test and modification make things better.

Failures are to be encourage! they should be thought of learning experiences. If everything works perfectly little is learned.

The hardest part of designing is getting the requirements right, which means ensuring that the right problem is being solve as well the solution is appropriate.

• Requirements made in the abstract are invariably wrong.
• Requirements by asking people what they need are invariably wrong.
• Requirements are developed by watching people in their natural environment.    

Getting a requirement right involves repeated study and testing: iteration.

Observe and study: decide what the problem might be, and use the results of the test to determine which part of the design works, which don’t… then iterate again through all four stages once again. Collect more design research if necessary, create more ideas, develop the Prototypes and test them.

With each cycle, the test an observation can be more targeted and more efficient. After the few iterations it is time to converging upon a solution. The several different Prototypes ideas can be collapse into one.

^{Taken from the Don Norman book “the design of everyday things”}