Diary study for a hardware product

THE CHALLENGE

Ahead of launching a new hardware device that connects to the car-maintenance app, the team needed to understand how people actually live with it. Not just whether they can complete a task in a session. I led a mixed-methods, diary-based study to observe long-term behaviour, uncover friction and evaluate whether the hardware-to-app experience felt intuitive, reliable and genuinely valuable.

Role

Research lead, end to end

Method

Mixed-methods diary study

Used for

Product pre-launch

Depth takes time, and the launch would not wait.

A three-week study across three tasks generates a large volume of qualitative and quantitative data. The real work was distilling it into clear, actionable findings: summarising and synthesising the main insights while deliberately setting aside secondary ones for future iterations. The work was done under time pressure, because the team needed results to inform imminent decisions.

Keeping participants engaged across the full three weeks was the other challenge. A diary study is only as good as its retention, so consistent participation had to be actively maintained rather than assumed.

PROCESS

I clarified exactly what we needed to know before launch: whether pairing, alerts and everyday use felt reliable and valuable over time, not just at first open.

Define the problem

Prepare research goals and the study plan

I designed the diary-study methodology and research plan, structured over three weeks and three tasks to surface long-term behaviour rather than first impressions.

Recruit participants and prepare materials

I recruited participants representing different car types and usage patterns. I created the daily tasks and prompts that would guide consistent, comparable reporting.

Run the study and support participants

I monitored entries throughout and provided ongoing support to participants, which is what held retention across the full duration.

Collect, analyse the data, synthesise insights and share recommendations

I analysed both qualitative and quantitative data, prioritising the findings that could change pre-launch decisions. I turned findings into concrete recommendations for product, design and engineering. Including contextual tips that helped users interpret alerts and insights they had been misreading.

Confusion around alerts and data interpretation, gaps in feature discovery, friction in pairing hardware with the app and the emotional responses (such as frustration, trust, expectation), that a single-session usability test would never have captured.

WHAT THE DIARY FORMAT SURFACED

ONBOARDING

Significantly improved onboarding success rate before launch by catching friction early.

DESIGN

Shaped final design decisions for both the device and the app.

CLARITY

Simplified alert and data communication based on observed confusion, not assumptions.

Identified where users lost confidence, and where perceived value could be built.

REFLECTION

The diary format earned its cost. It gave us the depth and realism to refine the product before release and exposed issues that would have stayed invisible in traditional testing - ultimately shaping a smoother, more trustworthy hardware-and-app experience.

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