The length of responses to open-ended questions - A comparison of online and paper questionnaires in terms of a mode effect

The existence of a mode effect is assessed using data from two matched groups of 15- to 16-year-olds (n = 466) who completed a questionnaire either as a Web-based online version or an "optical mark recognition" paper version. This article focuses specifically on the length of answers to four open-ended questions included in the questionnaire. It was found that although the online answers to three of the four questions tended to be slightly longer than those from the paper version, the differences were not statistically significant. Other factors, specifically gender and educational aspirations, appeared to have much more influence on the length of answers to open-ended questions than the mode of delivery per se. The findings do not provide conclusive evidence of any mode effect with respect to the online delivery of questionnaires.