title: Assessing the validity of sexual behaviour reports in a whole population survey in rural Malawi.
abstract: BACKGROUND
  Sexual behaviour surveys are widely used, but under-reporting of particular risk behaviours is common, especially by women. 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 sexual behaviour. Validity of responses was assessed by analysis of probing questions; by comparison of results with in-depth interviews and with Herpes simplex type-2 (HSV-2) seropositivity; by comparing reports to same sex and opposite sex interviewers; and by quantifying the partnerships within the local community reported by men and by women, adjusted for response rates.
  
  
  RESULTS
  6,796 women and 5,253 men (83% and 72% of those eligible) consented and took part in sexual behaviour interviews. Probing questions and HSV-2 antibody tests in those who denied sexual activity identified under-reporting for both men and women. Reports varied little by sex or age of the interviewer. The number of marital partnerships reported was comparable for men and women, but men reported about 4 times as many non-marital partnerships. The discrepancy in reporting of non-marital partnerships was most marked for married women (men reported about 7 times as many non-marital partnerships with married women as were reported by married women themselves), but was only apparent in younger married women.
  
  
  CONCLUSIONS
  We have shown that the under-reporting of non-marital partnerships by women was strongly age-dependent. The extent of under-reporting of sexual activity by young men was surprisingly high. The results emphasise the importance of triangulation, including biomarkers, and the advantages of considering a whole population.
authors.affiliation: Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom. judith.glynn@lshtm.ac.uk
authors.forename: Judith R
authors.initials: JR
authors.lastname: Glynn
authors.forename: Ndoliwe
authors.initials: N
authors.lastname: Kayuni
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Banda
authors.forename: Fiona
authors.initials: F
authors.lastname: Parrott
authors.forename: Sian
authors.initials: S
authors.lastname: Floyd
authors.forename: Monica
authors.initials: M
authors.lastname: Francis-Chizororo
authors.forename: Misheck
authors.initials: M
authors.lastname: Nkhata
authors.forename: Clare
authors.initials: C
authors.lastname: Tanton
authors.forename: Joanne
authors.initials: J
authors.lastname: Hemmings
authors.forename: Anna
authors.initials: A
authors.lastname: Molesworth
authors.forename: Amelia C
authors.initials: AC
authors.lastname: Crampin
authors.forename: Neil
authors.initials: N
authors.lastname: French
mesh_terms: D000293:Adolescent; D000328:Adult; D044966:Anti-Retroviral Agents / Q000627:therapeutic use; D005260:Female; D006306:Health Surveys / Q000706:statistics & numerical data*; D006801:Humans; D007407:Interviews as Topic; D008295:Malawi / Q000453:epidemiology; D008297:Male; D008393:Marriage; D008875:Middle Aged; D015203:Reproducibility of Results; D058028:Research Report; D012424:Rural Population / Q000706:statistics & numerical data*; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D044966:Anti-Retroviral Agents