Survey textbooks suggest that long questionnaires should be avoided, and a careful reading of the available empirical evidence confirms the negative effects of substantial length on both response rates and the quality of those responses which are obtained. Data is presented from a lengthy survey in Britain in 1987. Analysis of reasons for nonresponse to this survey suggest that length may indeed have been a significant disincentive to respond for many. However, no effect of length was found on item quality as measured by the number of responses given to open-ended questions. Unexpectedly, the variance in number of responses was greater when the questions were asked later in the questionnaire. The results are interpreted as resulting from the greater power that respondents gain as the survey proceeds.
The problemSurvey research is an expensive business; having gone to the expense of tracking respondents down, we often try to get as much from them as possible. While most would concede that increasing length beyond a certain point leads to an unacceptable reduction in both response rates and the quality of the data collected, there is no agreement about the timing of this critical point. In this paper, some findings are reported from a lengthy survey of work attitudes and work histories. We dwell briefly on the reasons for refusal given by non-respondents to this survey, which are commonplace but nonetheless frequently ignored by survey designers. The core of the paper concerns the results of an experiment conducted to test the effect of length of questionnaire on the responses to open-ended questions.
The literatureThe message from most survey textbooks is clear: don't make questionnaires too long. Failure to observe this rule will produce a decline in response rates,