by Jim Bradford, MediCHI Consulting
Posted: November 20, 2008
Bradford says: Devices with very small screens such as PDA’s and smartphones should not be considered as an input device for prescriptions or other medical note-taking.
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Citation: “The Relationship of Usability to Medical Error: An Evaluation of Errors Associated with Usability Problems in the Use of a Handheld Application for Prescribing Medications,” by Andre Kushniruk, Mark Triola, Ben Stein, Elizabeth Borycki, and Joseph Kannry, Medinfo 2004, pp 1073-1076.
People who should read this: (1) Physicians considering using handheld terminals, and (2) medical administrators concerned with the safety implications of handheld terminals
The Context: Using Personal Digital Assistants (PDA’s & smartphones) for writing prescriptions.
Review: Illegible handwritten prescriptions have produced safety concerns for over a century. As we enter the twenty-first century sophisticated new handheld devices hold the promise addressing this problem while simultaneously streamlining the way prescriptions are managed and monitored.
This paper evaluates a prescription writing system that replaces the traditional prescription pad with a Handspring Visor Pro personal digital assistant (PDA). The researchers recruited a group of ten volunteers all of whom were Internal Medicine physicians from the Mount Sinai School of Medicine. Each physician was given several medical scenarios and was asked to prescribe the appropriate medication and dosage using the handheld device. The doctors were asked to verbalize the diagnostics thinking leading to a particular prescription.
The physicians were videotaped as they used the device. In addition, a record was made of the actual interaction with the PDA. A list of slips and errors were compiled across all ten physicians (a slip is a small mistake-equivalent to a typo; an error is a larger mistake-generally based on a misunderstanding of device operation).
A subsequent analysis of the video revealed a number of usability errors in the design of the prescription software. The researchers then used a tabular method based on a timeline to correlate user slips and errors with usability problems. They reached the (not unreasonable) conclusion that the usability problems contributed to the medical errors. Most of the time, these errors involved dosage problems rather than the prescription of the wrong medicine.
The experiment revealed two problems that were common to almost all of the participants. The first related to the extremely small display area available on a handheld device. When a significant part of the available screen “real estate” was given over to the menu system needed to operate the device, insufficient space was left to show all of the actual prescription. The researchers believed that many of the dosage errors that occurred derived from the fact that the physicians could not see the entire prescription at a glance.
The second major usability problem contributing to the observed medical errors, was the fact that many of the default values for the prescriptions were wrong from the physicians point of view.
Conclusions: The problem with the small screen size is a serious issue. It is something that is not easily corrected by changing the user interface design. It became very clear during the experiment that physicians (with many demands on their attention) needed to review their notes (in their entirety) at a glance. This is something that physicians and administrators need to consider before adopting handheld devices. A careful tradeoff needs to be made between portability and usability.
Fortunately, the second major usability problem relating to dosage defaults can be corrected fairly easily by ensuring that developers consult with physicians when setting up the system defaults.
The bottom line: Devices with very small screens such as PDA’s and smartphones should not be considered as an input device for prescriptions or other medical note-taking.
