GCSE Design & Technology: The Iterative Design Process Revision Guide

Identifying a need and writing a specification

Good design starts with identifying a genuine need or problem, often expressed as a short design brief describing what is to be designed, for whom, and why. From the brief, a designer writes a design specification: a detailed list of criteria the finished product must meet, covering aspects such as function, size, materials, cost, target user, aesthetics and safety. The specification is used throughout the project to check that ideas, prototypes and the final product all meet the original requirements, and it may be updated as research and testing reveal new information.

Researching

Research can be primary or secondary. Primary research involves gathering new, first-hand information directly relevant to the project, such as surveys, questionnaires, interviews or observing potential users. Secondary research involves using information that already exists, such as textbooks, websites, existing products and disassembly (taking apart similar products to see how they work). A mood board, collecting images, colours, materials and styles, is a useful way of gathering and communicating visual research and inspiration before ideas are generated.

Generating and developing ideas

Idea generation techniques, such as brainstorming, help designers quickly produce a wide range of possible solutions without judging them too early. Promising ideas are then developed through annotated sketches, which combine drawings with notes on materials, dimensions, mechanisms and how the design works, alongside more detailed drawings and computer-aided design (CAD) models. Developing ideas often involves comparing options against the specification and combining the best features of several ideas into a stronger final concept.

Prototyping and iteration

A prototype is an early model of a design, which may be a rough mock-up, a CAD model, or a fully working sample, used to test and refine the idea before committing to final manufacture. Iterative design means repeating a cycle of designing, making and testing a prototype, gathering feedback from users or clients, and then refining the design in light of that feedback. This cycle may be repeated several times, allowing problems to be identified and solved early, which reduces the risk of expensive mistakes once a product goes into full production. Rapid prototyping technologies, such as 3D printing, allow physical models to be produced and tested quickly during this process.

Evaluating

Evaluation should happen throughout the design process, not just at the end. At each stage, ideas and prototypes are checked against the design specification to see whether they meet the required criteria, and user feedback is used to identify strengths and weaknesses. A final evaluation of the completed product should assess how well it meets the original brief and specification, and it may suggest further improvements for future versions.

Common mistakes

• Treating the design process as a strict one-way sequence, when in reality iterative design involves going back and forth between stages as testing reveals new information.
• Writing a specification that is too vague to be tested against, rather than specific, measurable criteria such as dimensions, cost limits or materials.
• Evaluating a product only on appearance, rather than checking it systematically against every point in the original design specification.