Letter to Grandma is a communication and clarity-testing technique that asks a designer or team to explain a product concept, service design, or complex idea in a letter addressed to an elderly relative with no technical background. The constraint is deliberately extreme — stripping away jargon, acronyms, assumed knowledge, and abstraction — and the difficulty of the exercise reveals exactly how clearly a team actually understands what they are building. If you cannot explain it to someone outside the field, you probably do not understand it as well as you think you do.
What It Is
The method involves writing a short letter (one page maximum) that explains a product, service, or design concept in plain language accessible to a non-technical reader. The letter must explain what the thing is, why it matters, what problem it solves, and how it works — using analogies, everyday language, and relatable examples rather than industry terminology. The completed letter is then used as a communication benchmark and a clarity test for all subsequent design documentation.
How to Run It
- Each team member independently writes their version of the letter — differences between versions reveal misalignment about what the product actually is.
- Share letters in the group and discuss: where do the explanations diverge? Where is the language clearest? Where does it break down?
- Identify the clearest explanations and the most effective analogies from across all letters.
- Synthesize a single agreed-upon plain-language explanation that the whole team endorses.
- Use this explanation as the baseline for all external communication: user onboarding, marketing copy, pitch decks, and customer service scripts.
- Revisit the letter whenever the product changes significantly to check that the plain-language explanation is still accurate.
If you can't explain it simply, you don't understand it well enough yet.
When to Use It
Letter to Grandma is most effective at the beginning of a project when team alignment on the core concept needs to be tested, before writing user-facing copy, before a stakeholder presentation where a clear single-sentence explanation will be required, and whenever a design has become sufficiently complex that the team has lost the ability to describe it simply.
Tips for Success
- Write the letter honestly — if you find yourself unable to explain something without jargon, that is diagnostic information about the design's clarity.
- Ban technical terms, acronyms, and industry buzzwords from the letter entirely.
- Read the letter aloud to someone outside the industry and watch where their attention drifts or their brow furrows.
- Use the best analogies from the letter in your actual product: if an analogy makes the concept clear in the letter, it will make it clear in the interface too.
