The questionnaires are tested in common browser types and versions. Heavily outdated browsers can be intercepted (provided relevant distortion effects are expected).
The questionnaires are iOS compatible and therefore suitable for iPad and iPhone.
Especially for pop-up surveys, each contact with the online questionnaire is counted in order to calculate return rates.
Through the login function or optional setting of a cookie at the end of the survey, logging IP numbers, or if applicable through subsequent data cleansing, respondents answering more than one questionnaire can be identified and excluded from the analysis.