Page 203 - THE DUTCH TALKING TOUCH SCREEN QUESTIONNAIRE

same time get a detailed insight in what caused these problems. These insights are useful input for further development of the TTSQ. Another benefit of choosing a qualitative approach was that it did not demand any reading or writing skills from the participants. In the eyes of the researchers, this increased the chances of being able to include people with low (health) literacy in the study. At the very least, it would make people who had problems with reading and writing able to participate. Eventually, the researchers succeeded in including six less-educated participants (max. primary school), of whom two had low basic reading and writing skills, into their study population of 24 people. The results of the study showed that no educational group in this research population stood out from the rest in the kind or number of problems that arose. All respondents recognized themselves in the outcomes of the questionnaire. The use of plain language and ICT within the TTSQ, however, had both positive and negative effects on the response processes. This is a valuable insight, which may not have been derived from more commonly conducted quantitative validity testing approaches, since these methods help researcher to detect problems, but do not provide a detailed view and deep understanding of the nature and causes of these problems. Validity testing methods used by other researchers A few researchers in previously-published studies on TTs have also assessed validity aspects of their tool. Two different approaches may be distinguished. In the study of Paiva et al. \[22\], 323 participants completed a paper- and-pencil version of the newly-developed questionnaire that was the subject of the study and would later on be digitalized for the TT. Fifty percent of this study population had less than 8 years of formal schooling. Five percent of the total population was illiterate. How illiteracy was determined was not reported in the article. Whether participants who had problems with reading and writing managed to complete the questionnaire, and if so, how they managed to do this, was not reported in the article either. The same article, however, reported that in another part of the study, in which the paper-and- pencil version of the questionnaire of subject was compared with its digital equivalent, 28% (15/54) of the participants had not been able to complete the paper-and-pencil version. Nine participants who did not manage to complete the questionnaire had inadequate, three had marginal and three had adequate health literacy. To determine General discussion 203 5