The three prototype kinds
The book identifies three prototype kinds — concept, throwaway, evolutionary — each with characteristic uses, costs, and failure modes.
Concept prototypes
For exploring preliminary ideas. Quick, cheap, often disposable.
Use for: brainstorming sessions, early stakeholder alignment, exploring whether a direction is worth pursuing.
Examples: paper sketches, storyboards, mood boards, foam mockups, role-playing.
Failure mode: artificial reality problem. A skilled designer can make any concept look plausible; the prototype's polish doesn't predict actual workability.
Throwaway prototypes
For testing specific aspects of a design.
Use for: performance benchmarks, A/B tests, single-flow user studies, technical spikes.
Examples: standalone interactive demos, wind-tunnel models, isolated code experiments.
Failure mode: scaling and integration problem. A throwaway that works in isolation may fail when integrated or at scale.
Evolutionary prototypes
For incrementally building toward the final design.
Use for: MVPs that grow into products, iterative startup development, products with uncertain requirements.
Examples: software MVPs, agile sprint outputs, lean startup builds.
Failure mode: tunnel vision. Iterations refine the current direction; teams may miss fundamentally better directions.
Picking the right kind
| Situation | Prototype kind |
|---|---|
| Exploring ideas; "is this worth doing?" | Concept |
| Testing one specific question | Throwaway |
| Iterating toward a final product | Evolutionary |
| Stakeholder alignment | Concept |
| Performance benchmark | Throwaway |
| Scaling a startup | Evolutionary |
The kinds aren't mutually exclusive. A typical project uses concept prototypes early (to align), throwaway prototypes mid (to test specifics), and evolutionary prototypes late (to ship and refine).
Combining the kinds
A common pattern:
- Concept prototypes to explore directions and align stakeholders.
- Throwaway prototypes to test specific risks (performance, user flow, integration).
- Evolutionary prototyping to build the actual product, informed by what concept and throwaway prototypes revealed.
Each kind catches different issues; using all three reduces the risk of any single failure mode.
Resources
- Lidwell, Holden, Butler — Universal Principles of Design (2003).
- Schrage, M. Serious Play (1999).
- Brooks, F. The Mythical Man-Month (1995).
- Boehm, B. "A Spiral Model of Software Development and Enhancement" (1986).