Running a usability study with children is never straightforward. Children at different developmental stages interact with devices in vastly different ways, and involving caregivers adds another layer of complexity. In this project, we partnered with a client to assess a reusable nebuliser designed for home use by paediatric patients. Our goal: uncover how real children and caregivers used the device, identify where things broke down, and provide recommendations to improve safety, clarity, and ease of use.

Challenge

Evaluating a device with such a broad age range meant we had to plan for:

• Different modes of interaction: Caregiver lead use (3–7 years), co-use (8–12 years), and independent use (13–17 years).

• Varying cognitive and motor skills: From toddlers with limited dexterity to teens managing chronic conditions solo.

• Communication barriers: Young children often can’t articulate issues, requiring us to observe subtle signs of confusion or discomfort.

Each group brought a different set of cognitive, physical, and emotional needs. Some children couldn’t articulate what confused them. Some wanted to take control. Others became anxious, distracted, or shy. Caregivers stepped in—but often masked design flaws in the process.

In short: one device, many users, many contexts.

Our Approach

We designed a study that reflected real-life scenarios—morning routines, post-sport treatment, late-night care—across 29 families in a simulated home environment.

Our methods included:

• Age-appropriate task scenarios tailored to likely use cases

• Observation and video review to catch subtle signs of confusion or workarounds

• Semi-structured interviews with caregivers—and with children where possible

Flexibility was key. We adapted each session in real time based on the child’s needs, using toys, games, and gentle prompting to create a positive, realistic environment.

Lessons Learned

1. Younger children are unpredictable: Some lost interest mid-task, others became anxious or shy. Simulating real use was key, but we also needed to adapt sessions on the fly and rely heavily on caregiver interpretation. A good assortment of toys and sweets was vital!

2. Caregivers often compensate for design flaws: Parents “made it work” when instructions were unclear or assembly was difficult. These compensations pointed to design opportunities that might otherwise have been missed.

3. Sometimes it was the children that got things right and the parents that went wrong: The children sometimes benefitted from having no preconceived ideas of how things should behave, so worked with what they had in front of them. The parents however came with years of prior experience of other devices, meaning sometimes their expectations led them astray.

4. Teenagers want autonomy—but design can undermine that: Older users wanted to manage their treatment solo, but unclear feedback (e.g., confusing LED indicators) left them unsure whether the device was functioning properly.

5. One-size-fits-all doesn't work: The same instruction manual or device design won’t meet the needs of a 4-year-old and a 16-year-old. Paediatric devices must be adaptable—not just smaller versions of adult tools.

Design Recommendations We Delivered

Based on our findings, we proposed specific improvements:

• Colour-coded components and click-to-lock parts for intuitive assembly.

• Instructional materials intended for children and teens, using visuals and simplified text.

• Clear multimodal feedback (e.g., audible and visual cues) for device status.

• Training videos or mobile applications to help all users understand how to interact with the device.

• Illustrated cleaning guidance broken down into clear steps.

Let’s Build Better Together

Designing for children isn’t just about scaling down. It’s about thinking differently. We help teams create safer, smarter, more usable medical products for the real world—no matter how young the users.