title: Missing or contradictory answers on questionnaires--a valuable source of information.
authors.forename: G
authors.initials: G
authors.lastname: Joubert
authors.forename: E
authors.initials: E
authors.lastname: van der Ryst
authors.forename: F
authors.initials: F
authors.lastname: Steyn
authors.forename: J
authors.initials: J
authors.lastname: le Roux
mesh_terms: D005260:Female; D015658:HIV Infections / Q000517:prevention & control*; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D013019:South Africa; D011795:Surveys and Questionnaires