Interviews or postal questionnaires? Comparisons of data about women's experiences with maternity services.

Surveys by personal interview are often assumed to be superior to those conducted by mail questionnaire. An experimental study of experiences and attitudes of 800 newly delivered mothers revealed surprising advantages to postal surveys: they are cheaper, more easily repeatable, and minimize interviewer effects. While response rates differed, the quality of responses was similar, except between middle- and working-class mothers. Postal surveys can be used with considerable assurance in national studies of fairly intimate experiences of pregnancy and delivery.