THN Design
Trent Nguyen · Portfolio
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All research resources Research Method · Generative / Discovery · longitudinal

Diary Study

Capturing behavior and experience over time, as it happens rather than in retrospect. Good for understanding longitudinal patterns, emotions, and low-frequency events.

Use When
Generative / Discovery
Time Needed
2-6 weeks total: a data collection window of 1-4 weeks, plus setup and synthesis time.
Type
longitudinal
Category
Generative / Discovery
Generative / Discovery · Use when you need to understand people, context, and problems.
Diary Study
longitudinal
When to Use It

Where this fits in the process.

Early-to-mid discovery, when the behavior you care about happens over days or weeks rather than in a single session.

Time Investment

How long it takes.

2-6 weeks total: a data collection window of 1-4 weeks, plus setup and synthesis time.

What You'll Need

Before you start.

A screener, a logging tool or app, a clear entry prompt and cadence, and check-ins to keep participants engaged.

What It's Good For

The kinds of answers you get.

Capturing behavior and experience over time, as it happens rather than in retrospect. Good for understanding longitudinal patterns, emotions, and low-frequency events.

Watch Out For

Where it falls short.

High dropout rate. Self-reported data is inconsistent. Needs careful screener design and check-ins to keep participants engaged.

Let's Connect

Need research-backed UX leadership on your next engagement?

Whether you're rethinking a flagship product or trying to make sense of complex user behavior, I'd love to talk.

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