What do Prototypes Prototype?
Stephanie Houde and Charles Hill. 1997. (View Paper → )
We propose a change in the language used to talk about prototypes, to focus more attention on fundamental questions about the interactive system being designed: What role will the artifact play in a user's life? How should it look and feel? How should it be implemented? The goal of this chapter is to establish a model that describes any prototype in terms of the artifact being designed, rather than the prototype's incidental attributes By focusing on the purpose of the prototype—that is, on what it prototypes—we can make better decisions about the kinds of prototypes to build. With a clear purpose for each prototype, we can better use prototypes to think and communicate about design.
This paper shifted the industry conversation away from describing prototypes by their medium (e.g., "paper prototype" or "high-fidelity prototype") toward their purpose: testing role (what the product does for users), look and feel (user experience), or implementation (how it works technically). This framework remains fundamental in UX and product development, influencing how teams plan and communicate about prototypes.
Key Takeaways for Product Managers:
- Focus on purpose over medium: Choose prototyping methods based on what questions need answering, not arbitrary notions of fidelity.
- Different audiences need different prototypes: Technical teams, executives, and users may each require different prototype types.
- Build multiple prototypes: Complex products often require separate prototypes for role, look and feel, and implementation rather than attempting one all-encompassing prototype too early.
- Be explicit about what's being tested: Clearly communicate what aspects a prototype addresses and what it doesn't to avoid misinterpretation.
The model continues to help PMs make more efficient prototyping decisions, saving time and resources while answering the most critical product questions at each development stage.
The model presents a triangular framework for understanding what aspects of a design a prototype is meant to explore.
The Three Dimensions
- Role: Explores questions about what function the product serves in a user's life and how it's useful to them. Role prototypes answer questions like: What problem does this solve? How will it fit into users' workflows? What value does it provide?
- Look and Feel: Explores the concrete sensory experience of using the product - what users see, hear, and feel when interacting with it. These prototypes answer questions about visual design, interaction patterns, and the overall user experience.
- Implementation: Explores the technical underpinnings - how the product actually works "under the hood." Implementation prototypes answer questions about technical feasibility, performance, and architecture.
The centre of the triangle represents a fourth category:
- Integration: Explores the balance between all three dimensions, representing a more complete experience. These prototypes attempt to address role, look and feel, and implementation simultaneously.
How to Use the Model For any given design problem, the model helps designers: 1. Identify which dimension(s) contain the most important open questions 2. Create prototypes specifically targeted at answering those questions 3. Communicate clearly to stakeholders which aspects of the design are being explored (and which aren't) The model suggests that early in the design process, it's often more efficient to create multiple targeted prototypes addressing different dimensions rather than attempting to create a single comprehensive prototype that tries to do everything at once. Each prototype is placed on the triangle based on which dimension(s) it primarily addresses, creating a visual way to communicate a prototype's purpose to team members and stakeholders.