Non-response

Abstract

In censuses or sample surveys, it happens inevitably that no value can be obtained for one or several measured variables from certain interviewed units. It is then said that there is non-response within the survey. In the case where the values are taken from automated systems, this can include technical problems or breakdowns. On the other hand, when the survey resorts to questionnaires, the values can be missing for different reasons. Examples could include the unwillingness from the surveyed person, gaps in the value asked for, laxity of the interviewer who does not try to obtain responses to all the questions, lost questionnaires, etc. Note that a missing response here, in addition to a loss of information for example, is considered as being a non-response in the same way as a person refusing to respond. On the other hand, if the question allows a “no opinion” option, then this choice is not a non-response.