Diary Study
Asking participants to record their own experience over days or weeks, capturing behaviour no single session can show.
Some behaviour only exists over time: how a habit forms or fails in the first two weeks, what happens on the days somebody does not open the app, how a monthly process actually unfolds, when frustration accumulates rather than spiking. A single session cannot see any of it. A diary study asks participants to log entries as they go — prompted at intervals or triggered by events — producing a record of real moments instead of a recollection.
The main design problem is participation decay. Entries are rich on day one and thin by day five unless the burden is small and the prompts are specific. Ask for a photo or a voice note rather than an essay, prompt at the moment rather than at the end of the day, and plan a short interview afterwards to unpack what the entries mean — the diary tells you when something happened, the debrief tells you why.
In practice
A fintech app assumed users abandoned after onboarding because the product was confusing. A two-week diary study showed the drop was on days 3–5, when people were waiting for a bank verification that gave no status and no estimate. The app was not confusing; it was silent. Adding a progress state to the waiting period cut week-two abandonment by roughly a third.
Where teams get it wrong
- Asking for too much per entry, which produces detailed day-one logs and nothing after.
- Prompting at the end of the day, which collects recollection rather than the moment.
- No follow-up interview, leaving entries without the reasoning behind them.
- Running one over a period that does not contain the behaviour you care about.
- Paying only on completion, which biases the sample towards the highly motivated.
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Related terms
All terms- User ResearchThe systematic study of users' goals, behaviour and context — through interviews, observation and analysis — to inform what gets designed and built.
- User InterviewA structured conversation with someone who uses or might use a product, aimed at understanding their situation rather than collecting opinions.
- OnboardingThe experience that takes a new user from first opening a product to getting real value from it for the first time.
- RetentionThe share of users who keep using a product over time — the single best indicator of whether it delivers real, repeated value.