Design methods including the iterative design process, primary and secondary research, writing a brief and specification, generating and developing ideas, and using critical evaluation and feedback to refine a design.

What this dot point is asking

AQA wants you to explain the iterative design process, the research methods that inform it, how a brief becomes a specification, how ideas are generated and developed, and how critical evaluation and feedback are used at every stage to refine the design.

The iterative process

Iteration finds problems early, when they are cheap to fix, and keeps the user involved throughout. The power of iteration is economic as much as creative: the cost of changing a design rises steeply the further into development you are. A change on a sketch costs minutes; the same change after the injection-mould tooling has been cut can cost tens of thousands of pounds. By looping through cheap models and prototypes early, the iterative process pushes the expensive uncertainty out of the project before money is committed. It also avoids the trap of "design fixation", where a designer falls in love with the first idea and stops exploring; each cycle forces a fresh evaluation against the evidence. Iteration does have a cost, namely time, so designers balance the number of cycles against deadlines, stopping when the design reliably meets the specification rather than iterating forever.

Research and the brief

A good specification is specific and measurable so the final product can be objectively evaluated against it. The discipline is to turn every desirable quality into a testable criterion. "Must be durable" becomes "must survive 10,000 open and close cycles"; "must be easy to carry" becomes "must have a mass under 400 g and a handle of at least 25 mm diameter". These criteria become the yardstick the iterative process tests against, so the specification is not written once and forgotten but used at every evaluation. The two research types feed it directly: primary research grounds it in this product's real users and context, while secondary research supplies established data (anthropometric tables, standards, material properties) that would be wasteful to gather first-hand.

Generating, developing and evaluating

Ideas are generated through sketching, mood boards, brainstorming and morphological analysis, then developed and modelled. Morphological analysis is worth knowing by name: the designer breaks the problem into sub-functions (how it is held, how it opens, how it is powered), lists several solutions for each, and combines them in new ways to generate options that would not occur from sketching alone. Ideas are then developed through modelling and prototyping. Critical evaluation against the specification and feedback from users decides what to keep, change or discard before the next iteration. Critical here means evidence-based and honest: comparing the prototype's measured performance to the specification points and to user feedback, and being willing to reject a favoured idea that fails. This evaluation is the hinge of the whole iterative loop, because its output is the brief for the next cycle.