Wearable Fitness Trackers: A Comparative Usability Evaluation

This guest post is from graduate students Haley Vaigneur and Bliss Altenhoff. Haley and Bliss compared the usability of two fitness trackers as part of a graduate course in health informatics taught by Kelly Caine.


Wearable fitness trackers allow users to track and monitor their health. While these devices originated as a way for doctors to monitor chronically ill patients’ vitals, they have recently been developed and marketed for to a more general, health-conscious market. Equipped with advanced sensors such as accelerometers, users’ activity and sleep can be automatically tracked and then compared with their logged fitness goals and daily diet. Users can then use their statistics to help create or maintain a healthier lifestyle. Two examples of such devices are the Jawbone Up and Fitbit Flex, shown above.

Wearable technology is popular and has the potential to dramatically impact health (e.g. long-term health and activity data tracking, immediate syncing with Electronic Health Records (EHRs)). But these benefits can only be realized if the user is able to effectively use and understand these devices. This was the motivation for focusing on two of the most popular models of fitness trackers: the JawBone Up and FitBit Flex and their accompanying smartphone apps.

This study examined the usability of these two devices and their accompanying smartphone apps by having 14 participants (7 for Jawbone Up, 7 for FitBit Flex) perform a think-aloud test on five key features: Setup, Setting Goals, Tracking Diet, Tracking Activity, and Setting an Alarm. Participants then kept the wearable for three days and were encouraged to incorporate it into their normal routine. On the third day, participants completed the System Usability Scale survey and an informal interview regarding their experiences using the wearable.

Some of the key Jawbone UP findings were:

  1. Adding food or drink items was somewhat difficult due to unintuitive organization and unpredictable bugs. For example, one participant attempted to add a food item by scanning the bar code of a Lunchable, but the app added a Dr. Pepper to the log.
  2. Participants struggled to find the alarm settings, with one conducting a general web search for help to understand the Smart Sleep Window settings and how to save alarm settings.
  3. None of the participants were able to figure out how to communicate to the band or app that they would like to begin a workout. They didn’t realize that the Stopwatch menu option was intended to time the workout.

Some of the key findings of the FitBit Flex were:

Setting goals

Setting goals


What do I tap?

  1. Participants felt that the wristband (when using the appropriate sized band) was not uncomfortable or revealing and they were proud to wear it because it made them feel healthy.
  2. Users had a difficult time figuring out where to go on the app to set their health goals at first. Their instinct was to find it on the app homepage, or Dashboard, but it was under the Account tab.
  3. Some users had difficulty putting on the wristband, and several noted that it fell off unexpectedly. Users were also confused about where to “tap” the wristband to activate it, based on the instructions given in the app. The picture can appear to instruct the user to tap below the black screen, when the user actually needs to tap the screen directly, and firmly.
  4. Users did not realize that after turning Bluetooth on their phone, they needed to return to the app to tell the phone and wristband to begin syncing. They also noted that leaving Bluetooth on all day drained their phone battery.


    Bluetooth confusion

Based on time per task and number of errors the FitBit Flex performed better than the Jawbone Up on the five tasks. Users’ ultimate trust in the data, willingness to continue using the wearable, and general satisfaction with each wearable was heavily influenced by their initial experiences (first day). The positive initial think-aloud results for the FitBit Flex were also consistent with a more positive later experience and stronger acceptance of the wearable.

This study found that there is still much room for improvement in the usability of the accompanying smartphone apps. A major concern for these kinds of devices is keeping user interest and motivation, which can easily be lost through confusing or cumbersome designs. By striving to improve the human factors of the apps simultaneous to the capabilities of the actual wearables, there is great potential for greater user satisfaction, and thus more long-term use.

While activity tracking wearables are currently most popular with more tech-savvy, active people, these devices should be designed to be used by all ages and levels of experience users. These devices could change health monitoring drastically and give people the power and ability to make better choices, and live healthier lifestyles.

Haley Vaigneur is a graduate student in Industrial Engineering at Clemson University. Her concentration is Human Factors and Ergonomics, emphasizing on research in the healthcare field.

Bliss Altenhoff is a Doctoral Candidate studying Human Factors Psychology at Clemson University, where she received her M.S. in Applied Psychology in 2012.  She is a member of the Perception and Action (PAC) lab, where her research is concentrated on enhancing human perception and performance by enriching perceptual display technologies for laparoscopic surgeons. .

This material is based upon work supported by the National Science Foundation under Grant No. 1314342. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

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About Richard Pak

Associate Professor at Clemson University/Department of Psychology
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