In structured interviews for data collection, should the language of the used survey (not the discussion itself) be understood by the interviewee? Or is it fine to have it in another language that is interpreted by the interviewer only?
By far the most common practice in this area is to have interview translated into the respondent's own language. Before going into the field, this new version of the interview is usually "back translated" into the original language to assess the quality of the translation, which is then repaired if necessary.
As this process makes clear, allowing each interviewer to do their own translation has the risk of introducing too much variation into the wording of the original questions.
By far the most common practice in this area is to have interview translated into the respondent's own language. Before going into the field, this new version of the interview is usually "back translated" into the original language to assess the quality of the translation, which is then repaired if necessary.
As this process makes clear, allowing each interviewer to do their own translation has the risk of introducing too much variation into the wording of the original questions.
It's essential that your surveys respondents should answer in their own language. Obviously you can't just translate the statements and submit to them. But do a careful version of every statement and show to a pre-test group. Check if all the questionnaire is clear and well understood.
In this process you will achieve the instrument face validity.
Moreover, as professor Morgan said above, proceed a back translation of the questionnaire and submit to a native language individual of the original instrument.
By far this is what I have been doing in my research projects (we are on the same page). However, I notice there is a growing trend from local researchers to use the survey designed in English, while the mother tongue of the interviewees is Arabic!
I just wanted to know if there are any other opinions that I am not aware of.