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Diary research: Understanding UX in context
UX Research Glossary / Longitudinal Study
Longitudinal Study
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Longitudinal study is a research method that collects data from the same participants repeatedly over a period of time—ranging from weeks to years. It can be qualitative (e.g., tracking changes in attitudes or experiences through interviews or diary studies) or quantitative (e.g., measuring shifts in behavior or performance using repeated surveys or tests).
While often mentioned together, diary studies and longitudinal studies aren’t the same.
- A diary study is a qualitative method in which participants actively log their thoughts, experiences, or behaviors over time—usually through written entries, voice recordings, or digital tools.
- A longitudinal study is a broad research design study that tracks the same individuals across multiple time points using a variety of qualitative and quantitative methods.
That means all diary studies are longitudinal, but not all longitudinal studies are diary-based.