in a CBC survey we have 10 questionnaire versions with 12 choice tasks per version. There are two versions with a much smaller number of respondents than with the other versions (the surveys happened to be cancelled by respondents more often for the two respective versions). Thus, a few versions are under represented within the data. According to the Lighthouse studio manual, respondents are assigned to the questionnaire versions in a sequential order. How are the results affected, if the respondents are not approximately equally divided among all versions? Wouldn't it be better to randomly distribute the respondents to one of the questionnaire versions?