Page 134 - THE DUTCH TALKING TOUCH SCREEN QUESTIONNAIRE

Chapter 4
[45], tested. This is a debatable approach, because Frokjaer et al. consider effectiveness, efficiency and satisfaction as independent aspects of usability and state that it is risky to assume that there are correlations between these aspects [34]. Therefore, according to Frokjaer et al. satisfaction and efficiency outcomes should always be tested in combination with outcomes of effectiveness in order to give a complete and realistic overview of the usability of a tool. The results of the current study confirm the necessity of combining all three aspects of usability during usability studies. All participants in the current study, including participants who were not able to fully complete the questionnaire because of problems they had with operating the application, were satisfied with the usability of the DTTSQ. Looking solely at the results on satisfaction with the ease of use (which were also found in the comparable studies [44-50]) one could make the assumption that the DTTSQ is, usability-wise, ready to be released. Looking at the data found on efficiency within this study one can see that more experienced participants need less time to complete the questionnaire. This seems logical and matches the results of comparable studies [46,49]. In addition the completion- time was acceptable to all participants of the current study. Based on the efficiency results solely one could therefore also conclude that the DTTSQ was ready to be released. Looking at the results on effectiveness and specifically at the severity-rates of the problems that occurred during the response-process though, the researchers of the current study concluded that the usability of the DTTSQ needs to be improved to prevent problem 1, 5, 8 and 9 from occurring before it can be released.
The results of the current study show how difficult it is to strive for ‘inclusive design’. A lot of effort was put into developing a tool that is easy to use for potential future users at risk of exclusion from usage of mHealth tools [31]. By choosing a co-design strategy, development of a user friendly tool for people with diverse levels of education, literacy and digital skills was taken a step further than what was done in earlier comparable projects [44-50]. In the other projects users were involved in the evaluation process of the tools, but development was done by designers and health professionals. In spite of the user-centered development approach that was taken during the development process of the DTTSQ, the goal of inclusive design was not reached yet. Looking at the results of the current study the
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