An experiment comparing grids and item-by-item formats in web surveys completed through PCs and smartphones - Poster

More and more respondents complete web surveys via mobile devices. These devices vary at several levels from PCs: screen size, way to input the answers, portability, etc. In particular, we expect differences when grid questions are used due to the lower visibility on mobile devices and because, in questionnaires optimized to be completed through smartphones, grids are split up into an item-by-item format. This e-poster reports the results of a two-wave experiment conducted in Spain in 2015, comparing different indicators for grids and item-by-item formats across three groups of participants: PCs, smartphones not-optimized, or smartphones optimized. We found similar levels of inter-item correlations, longer completion times for grid questions for smartphone respondents, and in some cases less nondifferentiation for PCs.