It is common practice for survey designers to change how questions are asked and answered to better fit the survey mode. For example, the visual presentation of response lists in self-completion modes and face-to-face interviews with show cards allows the survey designer to use long lists. However, such lists are not feasible in telephone interviews relying solely on verbal communication, and this often leads to the use of radically different question formats between modes.

Two examples where the formats of the same question differ between modes are multi-coded questions and questions using scales. The multi-coded question that might appear in self-completion and face-to-face modes tends to be transformed for telephone into a series of Yes/No questions. Second, questions with response scales are often branched in telephone interviews; i.e. the question is converted into two or more questions, each with shorter response lists.

There has been limited research into the impact of these format differences on response, particularly across modes. The exception is the work carried out by Smyth, Christian and Dillman (2008) who compared multi-coded questions and series of Yes/No questions using telephone and web modes. In this presentation we will present the results from a mixed modes experiment in the UK that not only replicates the Smyth et al research but extends it by including face-to-face interviews as well as telephone interviews and web questionnaires. Furthermore, we include a comparison of branched and non-branched scales using all three modes. Finally, we use a cognitive interviewing follow-up to further explore the quantitative findings. This work is funded by the UK Economic and Social Research Council.