Item-by-item Versus Matrix Questions: A Web Survey Experiment

While the choice of matrix versus item-by-item questions has received considerable attention in the literature, it is still unclear in what situation one is better than the other. Building upon the previous findings, this study expands this line of research by examining whether the difference between the two question types is moderated by the number of response options. Through a web survey experiment, this study compares matrix and item-by-item questions with 2, 3, 4, 5, 7, 9, and 11 response options. Additionally, we also investigate the impact of the device used to complete the survey on data quality. The results show that straight lining and response time are similar between the two question types across all response lengths, but item nonresponse tends to be higher for matrix than item-by-item question, especially among mobile respondents. Also measurement models reveal measurement equivalence between the two question types when there are fewer than seven response options. For matrices with 9 or 11 response options, analyses reveal substantial differences compared to item-by-item questions.