Computer-aided personal interviewing. A new technique for data collection in epidemiologic surveys.

Most epidemiologic studies involve the collection of data directly from selected respondents. Traditionally, interviewers are provided with the interview in booklet form on paper and answers are recorded therein. On receipt at the study office, the interview results are coded, transcribed, and keypunched for analysis. The author's team has developed a method of personal interviewing which uses a structured interview stored on a lap-sized computer. Responses are entered into the computer and are subject to immediate error-checking and correction. All skip-patterns are automatic. Data entry to the final data-base involves no manual data transcription. A pilot evaluation with a preliminary version of the system using tape-recorded interviews in a test/re-test methodology revealed a slightly higher error rate, probably related to weaknesses in the pilot system and the training process. Computer interviews tended to be longer but other features of the interview process were not affected by computer. The author's team has now completed 2,505 interviews using this system in a community-based blood pressure survey. It has been well accepted by both interviewers and respondents. Failure to complete an interview on the computer was uncommon (5 per cent) and well-handled by paper back-up questionnaires. The results show that computer-aided personal interviewing in the home is feasible but that further evaluation is needed to establish the impact of this methodology on overall data quality.