UX Glossary · I
Iterative design
Designing in repeated cycles of build, test and refine, rather than attempting to get it right once.
Iterative design treats a design as a hypothesis to be tested and revised rather than a solution to be specified. Each cycle produces something concrete, exposes it to evaluation, and feeds the result into the next.
It is the core of the evaluation loop in ISO 9241-210, which requires designs to be assessed against requirements and refined until those requirements are met.
Why it beats getting it right first time
Not because designers are careless, but because the interesting problems are the ones nobody predicted. Fidelity is the lever: a paper sketch tested for an hour can invalidate a direction that would have cost a month to build.
The economics only work if the cycles are cheap. Iterating on production code is not iteration, it is rework, and teams that skip prototyping usually discover this once.
Where it fails
Two ways. Iterating without evaluating, which is just redrawing. And iterating on the solution when the problem was wrong, which produces a well-polished answer to a question nobody asked. Both are avoided by being explicit about what each cycle is testing.
In practice
Decide the question before the round. “Can people find the filter” is testable in an afternoon. “Is the design good” is not a question any iteration can answer.