Usability and why it’s important for your mobile study

Usability and why it’s important for your mobile study

Usability is like a well-designed bathroom. I should be able to go into one and expect toilet paper within an arm’s radius of the throne, a soap dispenser close enough to the sink so that I don’t drip water everywhere, and a wastebasket that I can practice my Stephen Curry pull up 3 pointer. When restaurants began replacing their old hand dryers with Dyson Airblades, the construction of the new technology hinted at how I should interact with it and provided just enough direction in the form of a pictorial, should need more assistance figuring it out. It was new, but also familiar.

Your mobile study has to be a well-designed bathroom. A participant should be able to navigate though your study easily and be able to accomplish set tasks without getting flustered or confused, which can lead to drop-off or faulty data. This is where the usability of your app has to shine. And for tasks that are researcher-driven, we have found that there are two key parts to achieving optimal usability: directive and user experience.


Since the launch of ResearchKit, some members of the research community have voiced their concerns about data integrity because the tasks are performed without the supervision of a proctor. In order for participants to provide accurate data, the app has to provide clear directive and leverage technology to aid the participant in completing the task.

Within ResearchKit, tasks are pushed to participants in the form of Activities. These Activities can be as simple as a multiple-choice survey, or as complex as setting up an additional device that may be required for your study.

In any scenario, its important to think about what you are asking the participant to do, and how he or she will be executing this activity. Let’s say for a muscular dystrophy mobile app study there is an activity that tests for arm stability. The participant is to hold the phone in one hand and extend his arm straight out in front of him for 1 minute, then switch to other hand and perform the same task. Here are two ways we can approach this.

  1. Provide an image of how the phone should be held with a countdown timer to let the participant know when to switch hands.
  2. Provide an image of how the phone should be held with a countdown timer to let the participant know when to switch hands. When the minute is up, provide haptic feedback (a vibration), alerting him that it is time to switch hands.

The second option with the addition of haptics drastically improves the usability of the app. A minute can be a long time and a user may become momentarily distracted by something else during this time. Switching hands late may result in false positives.

User Experience

The dynamic that changes with a mobile study app is that the participant is no longer on your time; you are on their time. She is not in your office at your disposal. She is at home and at work, with numerous opportunities for distractions and interruptions. Participants want the mobile research experience to fit into their lifestyle.

They want familiar controls and an exceptional user experience that they have been accustomed to from their iPhone or Android devices. While she may expect these things, the experience should almost feel invisible to her. Sometimes the best experience is to feel as if every control, button, or tool, is right where she expects it to be; it should not be overstated, it should simply be right.

When designing your mobile study app, rely on what users already know. Leverage their phone’s native operating system user interface (UI) when possible, allowing for a cohesive experience that marries right into the device that she considers an extension of her. Consider gesture controls — swiping, pinching, force touch — that are now second nature to the average smartphone user.

When introducing a new feature or an improvement upon an existing feature, like the Dyson Airblade, evaluate how the end user will approach it, what familiar or new experience you want him or her to feel. Do you need 20 different customizable ways to achieve the same task? Or is one or two streamlined ways sufficient? Some times a doorknob just needs to be a doorknob.

Let these two tenets be your guardrails when designing the usability of your mobile study. Of course the design will change and pivot depending on your participants. Your study’s cohort age, mobility, eyesight, and a number of other traits will ultimately guide the design process. The most usable bathroom doesn’t always translate to a modern hands-free experience; a bathroom at a senior home will have handrails, brighter lighting, lower shelf heights, and rubber mats to prevent slipping. All in the name of usability.