An Explanatory Study to Measure the Effect of an Expanded Target Interface for a Handheld Medication Order Entry Task

Abstract

This research experiment intended to determine whether an expanded target interface could improve a medication order task entered on a Personal Digital Assistant (PDA) compared to a standard interface. Subjects in this experiment used each of two simulated PDA medication order entry programs. This experiment required subjects to find items on two types of PDA interfaces in order to enter and complete a medication order. A repeated measures crossover design allowed users to experience both interfaces to assess individual responses to each interface. This study measured two primary objective measures (errors and time) and one subjective measure (workload) within the two interface versions. The expanded target interface performed exactly as the non-expanded interface except for when a subject tapped an item. The tapping and subsequent highlighting of an item onscreen in the expanded interface caused the item and any adjacent items to increase in font size and separate more from surrounding items. The expectation was that the expanded target interface would provide improved performance through reduced error rates and favorable user opinions and would differ from the non-expanded interface in time of order entry. Data collection was divided into two phases: 1. A sixty minute PDA data entry of typed medication orders consisting of five components (patient name, medication name, strength, dose amount and frequency) on one of five matching PDA screens. 2. Completion of a subjective survey for each of the two interfaces and a demographic questionnaire. A total of 113 subjects (43 males, 62 females and 8 unidentified) participated in five experimental data collection sessions. The expanded target interface did not reduce error rate significantly compared to the non-expanded interface. Further, the expanded target with its higher workload ratings compared to the non-expanded interface did not reduce the effort as expected for subjects in order entry tasks. A significant difference in time for order entry and workload ratings between interfaces in general existed, however it was the expanded interface which had a slower order entry time and higher workload ratings versus the non-expanded interface.