In a 1973 article about questionnaire length and response rate, it was argued that "common sense suggests that the shorter the questionnaire, the more likely a high response rate, and persons studying questionnaire efficiency have tended to accept this belief in spite of little empirical evidence to support it.... Surprisingly few studies actually have examined correlations between length of questionnaires and rate of response, and those studies that have done so generally have yielded confusing results." Not much has changed since then. Most of the research reviewed in the 1973 article concerns mail surveys. Since then, there has been some additional work on in-person interviews; however, the results are still confusing, the conclusions are still not clear, and questionnaire designers still aim for shorter questionnaires under only the logical assumption that longer interviews will result in higher nonresponse. The purpose of this paper is to present a thorough review of the literature on this topic, covering different modes of administration as well as one- time and panel-study findings.