Obtaining health information from farmers: interviews Versus postal questionnaires in a New Zealand case study

Purpose. To compare the effectiveness of interviewer-led and postal surveys in gathering adequate health data for occupational health programmes among farmers. Methods. Two cross-sectional studies of farmers from southern New Zealand were conducted. Farms were randomly selected from the public land valuation roll and all farmers and farm workers invited to participate in the farmers' health study. First, 477 farms were invited to participate in an interviewer administered questionnaire and health check; and second, a further 432 farms were selected and invited to participate in a self-administered postal survey. Both groups completed the same questionnaire. Results. The response for the interviewer-led and postal surveys was 65.4% and 51.6% respectively. The 2 groups differed demographically, with fewer young farm workers in the postal survey, but were similar in all areas of health information collected, except that men in the interviewer-led survey were significantly more likely to have a psychological disturbance than men in the postal survey (chi 2 =5.06, df=1, p=0.024). Conclusions. Despite the interviewer-led survey having a higher response rate, the postal survey produced similar health data, which is adequate for planning occupational health programmes for farmers. Extra effort should be made to recruit younger farm workers in future research.