Iterative design

Iterative design is a design methodology built on a repeating cycle of prototyping, testing, analyzing and refining a product or process. After each version is tested, changes and refinements are made, with the aim of steadily improving quality and functionality, and interaction with the system being designed serves as a form of research that informs and evolves the project. It has long been used in engineering, for example in the plan, do, check, act cycle of the 1960s and in DMAIC within the Six Sigma framework, and it is linked to object-oriented programming and to Barry Boehm spiral development. The process can be applied throughout new product development, though changes are easiest and cheapest early on. It starts with a prototype, which a group not tied to the product evaluates, and the feedback is built into the next iteration until user problems fall to an acceptable level. It is common in human computer interface design, where a design is shown to test users, problems are noted and the interface is refined, and in website design, where change after release is practical.