Grid and Item-by-Item Formats in PC and Mobile Web Surveys
While grids or matrix questions are a widely used format in PC web surveys, there is no agreement on the format in mobile web surveys. We conducted a two-wave experiment in an opt in panel in Russia, varying the question format (grid format and item-by-item format) and device respondents used for survey completion (smartphone and PC). The 1,678 respondents completed the survey in the assigned conditions in the first wave and 1,079 in the second wave. Overall, we found somewhat higher measurement error in the grid format in both mobile and PC web conditions. We found almost no significant effect of the question format on test–retest correlations between the latent scores in two waves and no differences in breakoff rates between the question formats. The multigroup comparison showed some measurement equivalence between the question formats. However, the difference varied depending on the length of a scale with a longer scale producing some differences in the measurement equivalence between the conditions. The levels of straightlining were higher in the grid than in the item-by-item format. In addition, concurrent validity was lower in the grid format in both PC and mobile web conditions. Finally, subjective indicators of respondent burden showed that the grid format increased reported technical difficulties and decreased subjective evaluation of the survey.