For centuries, historians have studied personal diaries to glean unvarnished views of the past. As an intimate account, a diary forgoes the spin and euphemism of official records, offering an authentic glimpse of day-to-day experiences. Likewise, modern social scientists ask experiment subjects to keep a personal diary for collecting unaffected thoughts. Today, customer-centered businesses apply that same principle through diary studies to understand how products and services fit in customers’ lives.

So, what exactly is a diary study?

A diary study is a research method in which participants report thoughts and behaviors in their natural environment over several days or months.

Diary studies are split into two types — structured and unstructured.

1. Unstructured studies are open-ended, containing more participant-driven responses. Imagine handing someone a journal with only loose guidelines about what to write. Unstructured diary studies are regularly used for exploratory research and are often the catalyst for more granular research.

2. Structured studies ask participants to answer pre-defined questions addressing specific topics, themes, or challenges.

Why use a diary study?

1. Low cost
   Who doesn’t like cheap things that provide high value? Not only can diary studies be cheap to conduct, they also enable us to “work while we listen.” Researchers can simultaneously run other research or work on unrelated tasks.

2. Natural context
   The goal of research is to gather unbiased feedback — and the feedback in diary studies is full of context. Diary studies allow the participant to relax in their natural environment. When a participant is comfortable, he is less likely to feel pressure about answering a question in a particular way.

3. Generate fresh insights
   We don’t know what we don’t know. A short or rigid research method like a structured interview or user interview will not always catch subtle insights. In addition to answering known questions, a diary study can help us uncover a laundry list of future considerations.

4. Qualitative and quantitative data
   Diary studies allow us to collect images, audio, locations, short answers, and survey data. Collecting multiple data types enables us to build a holistic view of our users.

5. Study progression
   Follow the journey of a customer mastering a product. MVPs and new feature releases are great opportunities for diary studies. Open the window to a user’s mind as they grow alongside a product. Observe the experience of a frustrating onboarding, the joy in discovering a hidden feature, or the ensuing boredom once a participant has explored all the nooks and crannies of a product.

There has to be a catch. What is it?

1. Communication
   This makes or breaks the study. Because of the longevity, it is important to establish a clear channel for communication between the researchers and participants. Lingering questions hurt the study results. Additionally, monitoring participants to ensure they are actively participating can be time consuming.

2. Data, data, data
   Allow yourself time to sift through and analyze findings. If there are multiple data types, it may take longer than expected.

3. Drop-outs
   Diary studies can become dull and time-consuming for participants. As the study churns along, participants sometimes disappear. Mini-milestones can keep the participants engaged.

What’s the verdict?

There’s a right time and place for diary studies. A diary study can provide indispensable insights but should not be treated as a one-size fits all solution. Define the research needs first, then determine if the needs align with the diary study benefits.

Tools

• Old school - pen and paper, camera, audio recorder

• Diary study products - dscout, Journey HQ

• Others methods - Google forms, private Twitter/Tumblr accounts, Twilio

Check out how Mozilla conducted a diary study.