Dr. Egon Dejonckheere

Egon does research in Emotion, Clinical Psychology and Abnormal Psychology. His most recent publication is 'The Bipolarity of Affect and Depressive Symptoms', featured in Journal of Personality and Social Psychology: Personality Processes and Individual Differences.

What is a daily diary study?

Daily diary methods are used to capture people’s thoughts, emotions, behaviors, and experiences across days in their everyday lives. In a typical study, participants report once per day, usually in the evening, using brief structured questionnaires delivered via a smartphone application or web-based platform.

Daily diary studies are part of the broader family of ambulatory assessment, which focuses on measuring processes in real-world contexts over time. Within this framework, they rely on repeated self-report to track how experiences change from day to day, showing close conceptual relations with approaches such as Experience Sampling Methodology (ESM) and Ecological Momentary Assessment (EMA).

Daily diary versus ESM / EMA: Key differences

Daily diary methodology shares the same core characteristics as Experience Sampling Methodology (ESM) and Ecological Momentary Assessment (EMA). All three approaches rely on repeated assessments over time, are conducted in natural environments, and are designed to capture within-person processes. This makes it possible to study how experiences such as mood, symptoms, or behavior fluctuate in daily life settings, rather than treating them as static or trait-like constructs. In this sense, they are built on the same methodological logic of sampling real-life experiences as they unfold, which fundamentally distinguishes them from laboratory research and cross-sectional surveys that typically provide a single, decontextualized snapshot.

The key differences lie in time scale, participant burden, and the role of recall. ESM and EMA typically involve multiple assessments per day and focus on real-time or near real-time measurement. This allows researchers to capture short-term dynamics and moment-to-moment changes with high temporal precision. Daily diary methods, in contrast, operate at the level of the day, asking participants to summarize their experiences over a defined time window, usually the past day.

This lower sampling frequency has both advantages and trade-offs. On the one hand, daily diaries are less demanding for participants, which makes them more suitable for longer study durations. On the other hand, they rely more strongly on short-term recall, meaning that participants must reconstruct their day rather than report in the moment. Although this recall period is relatively brief, it can still introduce biases, for example by overemphasizing salient or recent events.

As a result, daily diary studies provide a broader, day-level perspective on psychological processes, making them particularly useful for studying how experiences accumulate and evolve across days. At the same time, they trade off some of the temporal precision and immediacy that characterize ESM and EMA.

A special case: The Day Reconstruction Method

A practical way to resolve the trade-off between capturing experiences with high intra-day precision and relying on simplified end-of-day recall is the Day Reconstruction Method (DRM), developed by Daniel Kahneman and colleagues in the early 2000s. Rather than asking for a single summary about one’s day, the DRM structures recall by breaking the day into meaningful episodes.

Participants reconstruct their previous day as a sequence of episodes, much like scenes in a film, and report for each episode what they were doing, where they were, who they were with, and how they felt, and so on. By anchoring reports in concrete temporal and contextual cues, this approach improves recall and reduces reliance on heuristics such as focusing only on the most salient or recent moments. 

In doing so, the DRM provides a more fine-grained representation of daily experience than standard daily summaries, while remaining distinct from traditional cross-sectional surveys. Although it still relies on retrospective reporting, it has been shown to approximate momentary assessments more closely than traditional questionnaires and has been widely used in research on well-being, time use, and everyday experiences.

How to conduct a daily diary study: App-based versus web-based formats

When designing a daily diary study, one key decision concerns the mode of data collection: web-based surveys or smartphone application? Compared to traditional paper diaries, digital approaches already offer substantial advantages. They allow for automated time-stamping, ensure that data are securely stored, and reduce common issues such as backfilling or missing entries, thereby improving overall data quality.

However, compared to web-based surveys, smartphone applications are more seamlessly embedded in participants’daily lives. Because people carry their phones with them throughout the day, assessments can be completed in a natural and convenient way, without requiring participants to switch devices or interrupt their routines to sit behind a computer. In addition, apps allow researchers to deliver timely reminders and notifications. These prompts help ensure that entries are completed at the intended moment, improving adherence to the study design and reducing delays or missed reports.
A third important advantage is the ability to integrate additional data streams. Smartphone applications can collect passive sensing data throughout the day, such as location, activity, device usage or heart rate, providing valuable contextual information that complements end-of-day self-report. This information can even support context-assisted recall. By leveraging passive data collected throughout the day, participants can be prompted to reflect on specific moments with the support of contextual cues, which helps improve recall accuracy and provides a more detailed picture of daily experiences, similar to the DRM.

Taken together, this suggests that app-based daily diary study methods are not only a logistical improvement over paper or web-based formats, but also open up new methodological possibilities. By combining structured self-report with passive contextual data, they move daily diary research closer to the richness of momentary ESM and EMA, while maintaining the simplicity of a once-daily design.

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FAQ

01.

What is a daily diary study?

A daily diary study is a research method in which participants report on their experiences, activities or behavior once per day, typically in the evening. These reports are collected over multiple days, allowing researchers to examine how experiences change over time in real-world settings.

02.

How is a daily diary study different from ESM or EMA?

Daily diary studies, Experience Sampling Methodology (ESM) or Ecological Momentary Assessment (EMA) all rely on repeated assessments in daily life to study within-person processes. The main difference is timing. ESM and EMA collect data multiple times per day in real time, while daily diary studies summarize experiences at the level of the day. This makes daily diaries less detailed, but easier to implement over longer periods.

03.

When should I use a daily diary study design instead of ESM or EMA?

Daily diary studies are most useful when your research question operates at the level of the day rather than the moment. If you are interested in day-to-day changes, longer study durations, or reducing participant burden, daily diaries may be the better choice. If you need fine-grained, moment-to-moment dynamics on a short time scale, ESM / EMA is more appropriate.

04.

What is the Day Reconstruction Method (DRM)?

The Day Reconstruction Method (DRM) is a variation of daily diary methodology developed by Daniel Kahneman and colleagues. Instead of summarizing the day as a whole, participants reconstruct their day as a series of episodes and report on each one. This approach improves recall accuracy and provides a more detailed view of how experiences unfold across the day.

05.

Should I use a web-based or app-based daily diary study?

Both are digital options, but smartphone applications offer clear advantages. Apps are more seamlessly integrated into daily life, allow for push notifications and reminders, and can collect additional contextual data trough passive sensing. This makes app-based studies more reliable and opens up new possibilities such as context-assisted recall.

06.

Can daily diary studies include passive data?

Yes. When conducted via smartphone applications like m-Path, daily diary studies can be combined with passive sensing data such as location, physical activity, device usage, and so on. This additional context can enrich self-report data and improve recall accuracy.