Electronic health record on the go: Device form factor and Fitts' law

PURPOSE

With electronic health records (EHRs) becoming ubiquitous, computer use in exam rooms during patient-provider interactions is commonplace. Although computer use brings many benefits to providers, and patients generally rate computer-use as having a positive impact, the use of mobile devices could eliminate existing issues, for example allowing providers to enter or review records while face-to-face with patients. Using mobile devices increases flexibility of providers, but also creates challenges associated with the mobile device itself. For example, the form factor (i.e., display size) of the mobile device may affect provider performance, satisfaction and usability of the EHR. This study assessed the impact of the device form factor on usability of the EHR by measuring the most commonly used devices. This question relates to the applicability of Fitts' law, which does not predict differences in usability of devices varying in their form factor, assuming a linear scaling of the user interface.

PROCEDURES

Health care providers participated in this study by performing common EHR related tasks using devices differing in their form factor. Each participant performed these tasks on each of the devices. Interaction with a desktop computer served as baseline.

RESULTS

Usability and task load ratings for all mobile devices were significantly lower than for the desktop. Among the mobile devices, the iPad with its largest form factors performed best, where the iPhone performed the worst. The time to complete the tasks revealed that the mobile devices took more time to complete the tasks with the iPad requiring the least time among the mobile devices. Finally, in terms of error rates, all mobile devices had a significantly higher error rate than the desktop control. Again, the lowest error rate was observed with the devices that had the largest form factor.

CONCLUSIONS

The results of this study suggest that the form factor of mobile devices is of critical importance for usability and task performance with none of the mobile devices performing as well as the desktop. In addition, it appears that Fitt's law requires some additional examination in the context of touch screen devices. Given these results, challenges associated with mobile access to the EHR exist that need to be addressed in the future.