Reliability of questionnaire responses as compared with interview in the elderly: Views of the outcome of transurethral resection of the prostate

Three hundred and eighty-eightmen undergoing transurethral resection of the prostate for benign prostatic hypertrophy completed a presurgical questionnaire and three follow-up questionnaires 3, 6 and 12 months after surgery. The questionnaires covered details of prostatic symptoms, general health, and expectations and results of surgery. At each follow-up point 40 randomly selected patients were interviewed by two female research assistants. The response rate to the questionnaires was over 90% at each follow-up point while that for the interviews was lower at around 80%. We examine the reliability of the postal questionnaires in assessing health status by comparing questionnaire and interview responses, with a view to the wider employment of such a method in the follow-up of surgical patients. In general, and as reported elsewhere, responses to questions on easily defined topics are highly comparable between questionnaire and interview. Responses to more subjective questions are moderately reliable, but with a tendency for postal questionnaires to underestimate a patient's health problems. It is difficult to assess the reliability of the questionnaires with regard to questions of an intimate nature since such questions caused embarrassment during interview with consequent incomplete responses.