Design of Everyday Things Framework

Foundational design principles for creating products that are intuitive, discoverable, and understandable. The "bible of UX", applicable to physical products, software, and any human-designed system.

Core Principle

Good design is actually a lot harder to notice than poor design, in part because good designs fit our needs so well that the design is invisible. When something fails, users blame themselves, but the fault is almost always in the design. Great design bridges the gap between what people want to do and what the product allows: it is discoverable (you can figure out what to do) and understandable (you can figure out what happened).

Scoring

Goal: 10/10. Score 2 points per satisfied row of the Quick Diagnostic (5 rows = discoverability, evaluation, error recovery, mapping, constraints). Bands: 9-10 = users act without instructions, understand every outcome, and recover from any error; 5-6 = one gulf or error path is broken; <=3 = users must consult a manual or routinely blame themselves. Report the current score and the diagnostic rows failing it.

The Two Gulfs

Every interaction with a product requires bridging two gulfs:

USER                                    PRODUCT
  │                                        │
  ├──── Gulf of Execution ────────────────→│
  │     "How do I do what I want?"         │
  │                                        │
  │←──── Gulf of Evaluation ──────────────┤
  │     "What happened? Did it work?"      │

Gulf of Execution

The gap between what users want to do and what the product lets them do. Users ask: What can I do here? Which control do I use?

Bridge with: clear signifiers, natural mappings, constraints, familiar conceptual models.

Gulf of Evaluation

The gap between what the product did and what users understand happened. Users ask: What happened? Did it work? What state is the system in?