BACKGROUND: Sexual behaviour surveys are widely used, but under-reporting of particular risk behaviours is common, especially by @entity1 . Surveys in whole populations provide an unusual opportunity to understand the extent and nature of such under-reporting. METHODS: All consenting individuals aged between 15 and 59 within a demographic surveillance site in northern Malawi were interviewed about their @entity458 . Validity of responses was assessed by analysis of probing questions; by comparison of results with in-depth interviews and with @entity1703 ( @entity1704 ) seropositivity; by comparing reports to same sex and opposite sex interviewers; and by quantifying the partnerships within the local community reported by @entity1 and by @entity1 , adjusted for response rates. RESULTS: 6,796 @entity1 and 5,253 @entity1 (83% and 72% of those eligible) consented and took part in @entity458 interviews. Probing questions and HSV-2 antibody tests in those who denied sexual activity identified under-reporting for both @entity1 and @entity1 . Reports varied little by sex or age of the interviewer. The number of marital partnerships reported was comparable for @entity1 and @entity1 , but @entity1 reported about 4 times as many non-marital partnerships. The discrepancy in reporting of non-marital partnerships was most marked for married @entity1 ( @entity1 reported about 7 times as many non-marital partnerships with married @entity1 as were reported by married @entity1 themselves), but was only apparent in younger married @entity1 . CONCLUSIONS: We have shown that the under-reporting of non-marital partnerships by @entity1 was strongly age-dependent. The extent of under-reporting of sexual activity by young @entity1 was surprisingly high. The results emphasise the importance of triangulation, including biomarkers, and the advantages of considering a whole population.

Assessing the validity of XXXX reports in a whole population survey in rural Malawi.

@entity1 :: ('9606', 'Species') :: ['women', 'men'] @entity1704 :: ('10310', 'Species') :: ['HSV-2'] @entity1703 :: ('MESH:D006561', 'Disease') :: ['Herpes simplex type-2'] @entity458 :: ('MESH:D020018', 'Disease') :: ['sexual behaviour']
@entity458 :: (MESH:D020018,Disease) :: ['sexual behaviour']
