Text versus voice? A number of approaches have been suggested to optimise mobile survey response rates. Whilst addressing survey design can help for closed questions, what about open-ended ones? The presenters will share the results of an experimental study comparing classical text-input formats in self-administered mobile surveys with an alternative, voice-recognition-based procedure in mobile survey projects. They will report on the relative differences of these two formats on usability and non-response levels, and will provide practical recommendations for mobile survey projects.