Carrying out a survey is a complex, costly and time-consuming process. Traditionally, surveys were carried out using paper forms (PAPI). One of the problems is that data collected in this way usually contain many errors. Therefore, extensive data editing is required to obtain data of acceptable quality. This consumes a substantial part of the total survey budget. Rapid developments of information technology in the last decades of the previous century made it possible to use microcomputers for computer-assisted interviewing (CAI). A computer program containing the questions to be asked replaced the paper questionnaire. The computer took control of the interviewing process, and it also checked answers to questions on the spot. Application of computer-assisted data collection had three major advantages: (1) It simplified the work of interviewers, because they did not have to pay attention any more to choosing the correct route through the questionnaire, (2) It improved the quality of the collected data, because answers could be checked and corrected during the interview, and (3) it considerably reduced time needed to process the survey data, and thus improved the timeliness of the survey results.