A statistical analysis of response rates

This paper discusses in detail issues dealing with the technical aspects in designing and conducting surveys. It is intended for an audience of survey methodologists. The Danish National Institute of Social Research is an independent institution under the Ministry of Social Affairs. The Institute carries out surveys on social issues on encompassing a broad range of subjects. The Sustainable Financing Initiative Survey (SFI-SURVEY) is an economically independent section within the institute. SFI-SURVEY carries out scientific surveys both for the Institute, for other public organizations, and for the private sector as well. The SFI-SURVEY interviewer body has 450 interviewers spread throughout Denmark. There are five supervisors, each with a regional office, who are in contact with the interviewer body. On a yearly basis, SFI-SURVEY conducts 40 surveys. The average sample size (gross) is 1,000 persons. The average response rate is 75%. Since January 1999, the following information about the surveys have been recorded: · Type of method used (face-to-face or telephone) · Length of questionnaire (interviewing time in minutes) · Whether or not a folder was sent to the respondents in advance · Whether or not an interviewer instruction meeting was given · Number of interviews per interviewer per week · Whether or not the subject of the survey was of interest to the respondents · Interviewing month · Target group (random selection of the total population or special groups)