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The Effects of Touch Screen Technology on the Usability of E-Reading Devices

Eva Siegenthaler, Yves Bochud, Pascal Wurtz, Laura Schmid, and Per Bergamin

Journal of Usability Studies, Volume 7, Issue 3, May 2012, pp. 94 - 104

Article Contents


Methods

The following sections discuss the participants, apparatus and stimuli, and the design and procedures used in this study.

Participants

Twelve participants (6 female, 6 male) volunteered to participate in the experiment. The participants were students from the University of Bern. Their age ranged from 20 to 26 years. Because previous studies (Siegenthaler et al., 2010) showed that age is a critical factor in usability testing of electronic reading devices, we decided that a participant’s age should not exceed 26 years. None of the participants had previous experiences with e-reading or tablet devices (no iPhone users). Their mean subjective media competence as self-rated on a scale from 1 (very low) to 6 (very high) was 4.125. Self-reported cumulative reading duration per week was on average 16.83 hours.

Apparatus and Stimuli

Three e-reading devices were compared in this test: the Sony PRS-505 (without a touch screen), the Sony PRS-600 (with a touch screen), and the Apple iPad (first generation). Figure 1 depicts the three devices, and technical specifications are provided in Table 1.

Figure 1

Figure 1. The three e-reading devices compared in the usability test: left, Apple iPad; center, Sony PRS-600; right, Sony PRS-505.

Table 1. The Three E-Reading Devices Compared in the Usability Test

Table 1

There are big differences in the handling of the three devices. The Sony PRS-505, without a touch screen, has to be operated with buttons (see Figure 1). For example, when changing font size, users have to navigate through the main menu with the buttons. The Sony PRS-600 is equipped with a touch screen; the touch screen reacts relatively slow, which is caused by the e ink technology. The Apple iPad is equipped with a multi-touch screen, resulting in high touch sensitivity. Due to the fast development in the electronic market, newer versions of the devices will soon replace the existing devices. But the differences in touch screen technology will remain. There are still new devices without touch screens, and there are still technical limitations along with the different screen technologies. Therefore, the touch screen vs. button debate will persist.

Design and Procedure

Each participant tested all three devices sequentially within one session. The order of devices was counterbalanced between participants. Dependent variables were usability measures. Each participant was given a questionnaire to rate the navigation, design, handiness, and manageability of each device. An additional usability questionnaire with closed questions about usability and acceptance of the device, based on the questionnaire of Huang, Wei, Yu, and Kuo’s (2006), was given. We also measured each participant’s success rate and time it took to complete the seven usability tasks. The usability assessment lasted approximately 60 minutes.

The experiment took place in a quiet room at the University of Bern with constant artificial light conditions. First, participants were given instructions on how to complete each task and about the procedure of the experiment. After the instruction, we gave each participant written instructions on how to complete a series of use cases. The descriptions of each task the participants completed are described in Table 2.

Table 2. Task Descriptions and Requested Operations for Each Device

Table 2Table 2

1Because the highlighting function is not available on the PRS-505, participants had to insert a bookmark instead (accordingly, they had to find the bookmark in task 4 and delete the bookmark in task 5).

A time limit of two minutes was set for each task. If a task was not solved after this delay, it was considered as a fail. After solving the usability tasks, participants rated the different aspects of each device (such as design, navigation, handiness, and handling) on a scale: 1 (very bad), 2 (bad), 3 (rather bad), 4 (rather good), 5 (good), and 6 (very good). Based on an earlier study (Siegenthaler et al., 2010), we asked the participants the following evaluation questions:

After completing the usability tasks and the ratings, participants completed an additional questionnaire with closed questions about usability and acceptance of the device based on the questionnaire by Huang, Wei, Yu, and Kuo (2006). The questionnaire contained eight items in the German language and assessed the aspects of learnability, handling, and errors of a device. Answers were given on a five-point Likert scale from 1 (strongly disagree) to 5 (strongly agree).

 

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