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Ergonomics Product Development of a Mobile Workstation for Health Care

Risto Toivonen, Dong-Shik Choi, and Nina Nevala

Journal of Usability Studies, Volume 7, Issue 1, November 2011, pp. 40 - 50

Article Contents

Materials and Methods

The following sections discuss the mobile workstation features, the procedure used in this study, and the expert and participant evaluations of the workstation.

The Tested Mobile Workstation Prototype

The mobile workstation prototype was called SPARKe 54.1, as named by the prototype design company—Spark Ergonomics Oy Ltd (see Figure 1). The workstation could be equipped with either a laptop or a desktop computer. A laptop computer could be installed under the lockable cover case and operated by an external keyboard and a mouse, or it could be laid on the cover. For the external keyboard, there was a separate keyboard tray with a slide-out mouse tray and mouse cubby (on the right side of the keyboard tray). The mouse tray on the cover of the cart could be pulled out to the left or right of the cover. During the study only laptop computers were used, and they were operated in both possible installation settings. Additional accessories installed on the prototype were a storage basket and a rack for an additional battery.

Figure 1

Figure 1. Features of the tested mobile workstation: 1 - foot pedal for adjusting height, 2 - storage basket, 3 - rack for an additional battery, 4 - keyboard tray, 5 - case for the computer, 6 - lockable cover for the case, 7 - higher mouse tray, 8 - combined mouse tray and mouse cubby (lower mouse tray), 9 - lockable wheels (in front of the cart)


This usability study was part of a product development process in which the expert evaluation and the user study data were given to the company that developed the mobile workstation prototype. Figure 2 illustrates the iterative design process. For the first phase of the study, experts evaluated a mobile workstation prototype and provided feedback. The experts’ feedback was integrated into the design of a redesigned mobile workstation prototype. The redesigned prototype was tested during the second phase of the study, the user study phase. Participants in the user study used the redesigned workstation prototype during one day in actual work situations in a hospital.

The outcome of both the expert review and the user study was a list of requirements for a usable, ergonomically designed mobile workstation. These requirements and feedback then were given to the company that designed the mobile workstation.

Figure 2

Figure 2. Procedure used during the prototype usability study. The implementation was performed by the prototype design company

Expert Evaluation

The process started with a 3-hour expert evaluation (Hignett, 1998) in which four experts in both ergonomics and technical, design, health science, and physiotherapy participated. In this hands-on session, the experts performed usage scenarios using the original prototype and commented on its physical design characteristics and the operation of the prototype. One of the experts acted as the chairman and led the discussion if needed. During the session, the experts were able to evaluate the use of the mobile workstation in simulated work situations. A laptop was placed on the prototype, but no hospital information system was available because the focus was strictly on the physical aspects of the mobile workstation.

The experts' comments were collected during the session as a list of recommended modifications. The mobile workstation developers then redesigned the prototype with the experts’ recommendations in mind. The recommendations also served as a basis for the questions raised in the user study phase.

User Study

The following sections discuss the participants and the methods used in the user evaluation portion of the study.


The intended users of a mobile workstation are both nurses and physicians. The practice of who operates the workstation during a round varies from ward to ward. In our study the participants were five physicians (two men, three women) and three nurses (one man, two women), aged 20-41 years (Table 1), from two hospitals in the Helsinki region of Finland. They all were right-handed and were accustomed to using a mobile workstation in their normal routine. They worked an average of 8 hours a week with their wards workstation. The volunteer participants gave their written consent to participate before the study began.

Table 1. Background Factors of the Participants (N=8), Mean and Range

Table 1


The mobile workstation was tested during and after a hospital round in a hospital ward (Figure 3). A round consists of seeing all of the patients who are in the hospital under the care of the physician who leads the round. There were two rounds in this study, and the number of patients seen during rounds was between 15 and 20. One physician made the round individually; other rounds had three participants (two physicians, one nurse). The activities performed included reading the patient’s information on the screen and entering text about the patient’s status using the keyboard. After the round, the video-recorded, think-aloud method was used to further evaluate the usability of the mobile workstation prototype. The participants were asked to report their thoughts as they used the prototype. We asked the following question to all participants: "How should this product be developed further?"

Figure 3

Figure 3. A physician using a mobile workstation during a typical morning round.

Visual analogue scales (VAS) were used to determine the usability features of the mobile workstation (Beauchamp, 1999; Lintula & Nevala, 2006; Nevala & Tamminen-Peter, 2004; Price, McGrath, Rafii, & Buckingham, 1983). The VAS is a 100 mm long continuous line with endpoints anchored by 0 (very poor) and 100 (very good). The VAS score is a measured distance (expressed in millimeters) from the 0 scale point. The participants were asked to mark on the line the point that indicated their evaluation of the feature. In addition, there was a question that asked, “How would you like to see this mobile workstation be further developed?”

The 10-item System Usability Scale (SUS) was used to determine the subjective assessment of the usability of the prototype (Brooke, 1996). It provided an easy-to-understand score from 0 (negative) to 100 (positive). The SUS is an effective, reliable, and inexpensive tool for measuring the usability of a wide variety of products and services (Bangor, Kortum, & Miller, 2008; Bangor, Kortum, & Miller, 2009; Dumas, 2003; Sauro, 2011).


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