Design brief and design criteria in QCE Design Unit 3

What this dot point is asking

QCAA wants you to be able to write a design brief that describes a human-centred design problem, and to convert the needs you analysed into design criteria that are specific and measurable. This is the bridge from explore to develop - it turns research into a contract that guides every idea and becomes the yardstick you evaluate against in resolve. Marks come from criteria that are genuinely measurable and that trace directly to evidenced needs, not vague aspirations bolted on at the end.

The answer

The design brief

A design brief is a concise written statement that frames the problem before any solving begins. In Unit 3 it describes a human-centred design problem for an identified person or group. A strong brief sets out:

• Who - the identified user or stakeholder, described enough to keep them present in every decision.
• The problem or opportunity - the need to be met, stated from the analysis, not assumed.
• Purpose - what the design is meant to achieve for the user.
• Context - where, when and how the design will be used.
• Constraints - the real limits the response must respect (budget, materials, size, time, safety, the user's capabilities).

The brief is the anchor. When ideation drifts or a feature is questioned, the brief is what the designer returns to.

Design criteria

Design criteria are the measurable conditions a successful response must satisfy. Each criterion should answer a need from the explore phase, and each should be written so you can test whether a design meets it. The discipline is to make criteria specific and measurable rather than vague:

• Weak: "must be easy to use."
• Strong: "must be operable with one hand by a user with reduced grip strength."

A useful test is to ask whether two people judging the same prototype would reach the same verdict against the criterion. If the criterion is measurable, they would; if it is vague, they would not.

Turning needs into criteria

The conversion is direct: every analysed need becomes one or more criteria.

1. Take an evidenced need from the analysis (for example, the user needs to stabilise food with one hand).
2. Restate it as a condition the design must meet (the design must hold food steady without a second hand).
3. Make it measurable (food must remain secure under normal cutting force, tested by the user completing a chopping task unaided).

Doing this for every priority need produces a criteria set that covers the real problem and nothing irrelevant.

How criteria steer develop

In the develop phase the criteria do two jobs. They guide ideation - you generate ideas aimed at the conditions that matter - and they drive convergence, because a criteria matrix scores each concept against the criteria to select the strongest. Without criteria, selection collapses into picking the idea you like best, which is indefensible to a marker.

How criteria become the evaluation standard

In the resolve phase the same criteria become the standard for evaluation and justification. You judge the resolved proposal criterion by criterion, with evidence, and justify how each is met. Because the criteria came from evidenced needs, meeting them is the same as meeting the user's needs - which is the whole point of human-centred design.

Constraints versus criteria

Constraints are fixed limits the design must not breach (a maximum cost, a safety standard). Criteria are conditions of success the design should meet as well as possible. Both belong in the brief and criteria set, but they play different roles - a constraint is pass or fail, a criterion is a measure of quality.

Worked example