layers-intro

/layers-intro

Load this skill at the start of any design session. It provides the framework context that all other /layers-* skills depend on.

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The framework

Layers of Product Design organises design work into seven layers across three zones. Layers have logical dependency: lower layers are foundations for upper ones. Weak lower layers create UX debt that propagates upward.

Reality — complex, contradictory, evolving. Source of all learning.

Problem space — knowledge gathered from reality:

1. Observed behaviour — what users actually do
2. The domain — concepts, terminology, and mental models that exist independently of any product
3. User needs — what we think users are trying to achieve, and why

Solution space — deliberate decisions about what to build: 4. Product & service strategy — which needs to serve, and what business outcomes to target 5. Conceptual model — objects, relationships, states, vocabulary — independent of any interface 6. Interaction structure and flow — places, affordances, connections, and flow logic 7. Surface — words, visuals, feedback, hierarchy — what users actually encounter

The layers are not a linear process. Enter anywhere — but always check whether the foundations below are sound.

Inspired by Jesse James Garrett's The Elements of User Experience (2000).

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Design is decision-making

Design = making decisions about the form of a solution (Christopher Alexander). Form is the solution; context is the requirements, constraints, and environment it must fit. Good design is good fit.

Four kinds of progress:

1. Making decisions — resolving something undecided
2. Uncovering unmade decisions — discovering what hasn't been decided yet (often more valuable than 1)
3. Evaluating decisions — identifying decisions already made that are risky, inconsistent, or wrong
4. Prioritising decisions — lower layers are more foundational and carry more risk if wrong

The job of every skill is to help the designer make better decisions — not to make decisions for them.