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Product design · Guide and template

Prototype the uncertainty that matters

Choose what a prototype needs to help you learn before spending time polishing it.

Go to the template

Before you start

You have an idea or proposed change, but need to check how it might work for people.

You’ll have: A focused prototype brief, a task to try and criteria for the next decision.

How to use it

  1. 1. Choose the risky assumption

    Write what must be true for the idea to help. Decide what an observation could support or challenge. Keep the scope to the part of the experience needed to learn about that assumption.

  2. 2. Build enough of the task

    Choose the simplest format that supports the interaction you need to observe. Include relevant content, error states and recovery where they affect the question. Make prototype boundaries clear and use fictional data.

  3. 3. Use the prototype to make a decision

    Try the task with relevant people and record what happened. Decide whether to change the design, investigate further or take it into delivery. Keep implementation and accessibility work visible when handing it over.

An example

Illustrative example: to learn whether people can recover from an incorrect address, prototype the error and correction path as well as the successful form submission.

Keep in mind: A prototype can help answer a design question. It does not prove production reliability, security or accessibility, and participant feedback is not a guarantee of adoption.

Use the template

Copy it into your own document or download the Markdown file. Fill it in with your team, using the guide above. No account or email is required.

Download .md

Preview the blank template
# Prototype learning brief

## Purpose
- Decision this prototype will inform:
- Assumption to investigate:
- Evidence we already have:

## Task and scope
- Person and situation:
- Task to try:
- Start and end of the flow:
- States needed to answer the question:
- Content and fictional data needed:
- Format and fidelity, with reasons:
- What is deliberately outside this prototype:

## Try it
- Relevant participants and access needs:
- Consent and session plan:
- What we will observe:
- Evidence that would challenge our assumption:

## Decide
- What happened:
- Change, investigate further or proceed:
- Why, and what remains uncertain:
- Implementation and accessibility follow-up:
- Owner and next review:

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Cumulative · Prototype the uncertainty that matters
Guide: https://cumulative.com.au/resources/prototype-plan

A prototype can help answer a design question. It does not prove production reliability, security or accessibility, and participant feedback is not a guarantee of adoption.