Diary studies for market research: The 2025 guide to smarter insights

During a diary study, your research participants keep a diary of their thoughts, feelings, and actions as they relate to the study’s subject. This usually happens over several days, weeks, or even months. 

You can then analyze each participant's diary entries to gain a deeper understanding of the situation you're studying.

Let’s say you want to know how adults across different age groups react to a software service’s updates over a period of two months. During this time, you make two major updates to the software. 

Using a diary study methodology, you can capture all the frustration, delight, rejection, and acceptance that comes with these changes as they’re happening. 

This is big. And with the advent of large language models (LLMs), it’s never been easier to organize, absorb, and analyze entries from research participants. 

Now, find out why diary studies are valuable and how to set up a successful one for your research.

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What’s the purpose of diary studies?

Diary studies give market researchers something they can’t get from other methods: a record of decisions, emotions, and behaviors as they actually happen over time.

Instead of relying on participants to remember past experiences in an interview or check a box on a survey, you see patterns unfold in real life. Importantly, you'll also see the context and major turning points that shape them.

In diary study user research, this longitudinal view is critical. Especially when you’re tracking how attitudes change in response to a product update or marketing campaign. 

The purpose of the diary study methodology is simple: to reveal the story arc behind user or customer behavior. 

With the full narrative from each participant in your study, you can uncover moments of friction, delight, or doubt. These insights, in turn, can directly inform your product strategy, messaging, and retention efforts. 

Example scenario of a diary study

Imagine you sorted users of a SaaS product into two groups to see how they react to two software updates over a two-month period. 

• Group A: The two major updates are rolled out incrementally over a two-month period.

• Group B: Each of the two changes is dropped all at once. One update drops on the first day of the first month and the second on the first day of the second month.  

Over the specified period, the diary study could show:

• First impressions of each update

• Initial frustrations each user felt

• Workarounds they took to keep things the same as older versions for as long as possible

• Praise and/or negative feedback they gave after adjusting to the change

• How long it took for users to get used to the update

Now imagine that both groups of users responded with frustration at every change point. 

By reading and analyzing diary entries, you realize that users in Group A feel constantly frustrated by each tiny change. Users in Group B, on the other hand, express a flood of initial frustration that levels out into praise after two weeks. 

Thanks to your diary study, you know that both update schedules cause frustration, but only the all-at-once approach allows sentiment to recover quickly. Using this information, you might decide to make major software updates in an all-at-once format. 

This critical insight could shape how you plan and communicate future releases.

Advantages of diary studies

• Real-time, in-context insights: Because diary entries are recorded as events happen, you see behavior, emotion, and decision-making in context.

• Longitudinal perspective: Unlike one-off research methods, UX diary studies capture change over time and reveal key patterns, habits, and shifts in sentiment.

• Rich qualitative data: Text, images, video, and even voice memos can all be part of a diary study. Modern diary study tools can store and organize these formats easily.

• Participant-led flexibility: In UX diary studies, participants often choose when and how to record their thoughts and experiences.  

• Stronger emotional resonance: By capturing frustrations, joys, and surprises in the moment, diary studies often uncover the ever-important “why” behind user decisions. 

• Lower costs: Diary study methodology can be conducted remotely, which can help keep expenses low. 

Disadvantages of diary studies 

• Participant fatigue and drop-off: Even motivated participants can lose steam after the first week. Without strong onboarding, incentives, and check-ins, the quality of your data can suffer.

• Inconsistent reporting: Some participants might skip entries or provide less detail over time, making analysis harder.

• Complexity of analysis: Large volumes of unstructured data can be time-consuming to code and interpret. (Although AI-assisted analysis is making this job much easier.)

• Potential self-report bias: Participants might filter events in a certain way, especially if they have strong feelings about the subject.

• Higher logistical overhead: While they often cost less than surveys or short interviews, diary studies require more upfront planning, coordination, and ongoing involvement.

How to design your diary study

A successful diary study does two things:

1. Makes it easy for participants to consistently contribute

2. Makes it easy for researchers to efficiently analyze the results

Here's how to accomplish both goals in 5 easy steps: 

1. Define your overarching research question

Before you do anything else, define the exact behavior, decision, or sentiment you want to observe. 

This keeps your prompts focused and helps participants understand why their input matters.

Let's say your goal is to understand how changes in pricing affect subscription renewals. Your overarching research question might be this:

“How do customers’ perceptions of value shift in the weeks after an increase in subscription prices?”

Every prompt in your diary study can then be designed to explore this question.

To help answer it, come up with a list of supporting sub-questions that help answer the overarching question:

1. What is the customer’s immediate emotional reaction to the price change?

2. Which features do customers use more or less after the price change?

3. Does perceived value increase, decrease, or stay the same over time?

4. What behaviors, if any, show an intent to cancel or downgrade?

5. How do customers describe the trade-off between price and benefits?

6. What communication touchpoints influence customer sentiment during this period?

You can match each question to a specific diary prompt to help get the answers you’re looking for. 

2. Build your timeline

Once you know your overarching and supporting questions, map them onto a clear schedule. This will help you gather the right data at the right time. It also makes participation more predictable.

Let’s create a diary study example of what this could look like for the study we talked about in Step 1.

In the table below, “Q” refers to “subquestion.” Each number mentioned below corresponds to the appropriate subquestion we laid out in Step 1. 

So, for example, Q1 means subquestion #1, “What is the customer’s immediate emotional reaction to the price change?”

Mapping the sub-questions to your prompts and strategically placing them on the calendar does two things:

1. Helps you avoid overloading and overwhelming your participants

2. Ensures your team still gathers all the qualitative data needed to answer the overarching research question

3. Create participant-friendly diary entry formats

No one wants to write essays all day, every day, as part of a UX diary study. Even diarists run out of things to say, or the energy to write what they want to say. One of the biggest downsides of diary studies is the potential for participants to lose steam and stop regularly recording their thoughts.

A way to get ahead of this problem is to make it easy to record those thoughts.

Instead of just asking participants to fill a blank page with the day's insights, use multi-field layouts to break things up. For example, you might offer questions in this type of structure for the participants to fill out each day of the study: 

• A 1-5 rating of perceived value helps capture that day's sentiment at a glance.

• A checkbox list of any new or cancelled features they used that day (revealing behavioral changes).

• A list of short-response questions with prompts like “What happened,” “How I felt,” and “What I did next.” 

• A short free-text field for comments to help provide context around frustrations or praise.

4. Foster trust from the beginning

Your relationship with your research participants is like any relationship — it takes trust and communication to make it work. 

A 2024 case study, “Soliciting Diaries for ‘Real-Time’ Insights Into the COVID-19 Pandemic: Methodological Reflections on Using Digital Technologies to Engage the Public,” highlights the importance of trust.

This diary study example found that participants appreciated personal contact with the project team, as well as privacy assurances.

While participants felt very wary of their data getting misused, they also wanted to feel like they were having a personal conversation with another person. 

The researchers realized this only after the study had begun: “Midway through the project, the research team revised the diary approach based on the experience gained….it became increasingly clear that the diarists needed a personal counterpart to write to.”

In response to this realization, the researchers transformed the project website with a presentation that introduced the researchers in a personal way, including photos.  

This helped diarists feel more like they were speaking to real people (which they were) rather than writing into an abyss. 

Takeaways:

• If participants feel respected, safe, and like they’re actually talking to someone, they may be more likely to stick with a study and provide richer, more candid entries.

• Don’t be afraid to revise your strategy as you go. The more experience you gain, the better you’ll get at running diary studies for user research.

Here’s how to put trust and communication into practice for diary studies: 

• Kick off with clarity: Host a short 15-minute call or record a video walkthrough to explain the study’s purpose, why participants were chosen, and what’s expected of them.

• Reassure them about privacy: Make your privacy policies clear and easy to understand.

• Stay present: Commit to weekly updates (even if they’re brief) about how the study is progressing, what you’re noticing so far, and how close they are to completing milestones.

• Invite questions: Give participants an easy way to reach you if they feel confused, frustrated, or worried. Offer options like email, chat, or in-app messages.

5. Plan ahead for analysis before you start

Think ahead about how you’ll code and interpret the data. This upfront planning will save you from scrambling later when hundreds of diary entries start piling up. 

Decide in advance which data points you’ll track quantitatively (e.g., ratings, checkboxes) and which you’ll code qualitatively (e.g., open-text reflections).

If you expect a large volume of entries, consider integrating AI-assisted tools (like at least one study has already tried). 

Some prominent diary study tools include:

• dscout is widely used in UX research. Participants can upload text, photos, and videos as diary entries, and the tool includes researcher dashboards for tagging and analysis.

• Indeemo is a mobile-first ethnography and diary study tool. It supports video diaries, location capture, and contextual prompts.

• Recollective is an online research platform with diary modules, discussion boards, and multimedia options.

These diary study tools can help tag themes, identify sentiment shifts, and quickly surface outliers. 

Importantly, AI tools don't replace your team's judgment as researchers. But they can dramatically reduce the time it takes to move from raw entries to actionable insights.

How to incentivize UX research participants

Incentives are critical to help keep participants engaged over time. Because these studies often span weeks or months, motivation can fade without a clear reward structure.

Best practices for incentives include:

• Set expectations upfront: Be transparent about how and when participants will be rewarded.

• Reward progress, not just completion: Offer small incentives for consistent logging (e.g., weekly payouts) alongside a final bonus for finishing the project.

• Match effort with value: Diary studies demand more commitment than a short survey, so compensation should reflect that extra effort.

• Use flexible payout methods: Digital gift cards or cash-equivalent platforms like Tremendous make rewards quick and easy to deliver.

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