title: Improving the collection of knowledge, attitude and practice data with community surveys: a comparison of two second-stage sampling methods.
abstract: BACKGROUND
  Second-stage sampling techniques, including spatial segmentation, are widely used in community health surveys when reliable household sampling frames are not available. In India, an unresearched technique for household selection is used in eight states, which samples the house with the last marriage or birth as the starting point. Users question whether this last-birth or last-marriage (LBLM) approach introduces bias affecting survey results.
  
  
  METHODS
  We conducted two simultaneous population-based surveys. One used segmentation sampling; the other used LBLM. LBLM sampling required modification before assessment was possible and a more systematic approach was tested using last birth only. We compared coverage proportions produced by the two independent samples for six malaria indicators and demographic variables (education, wealth and caste). We then measured the level of agreement between the caste of the selected participant and the caste of the health worker making the selection.
  
  
  RESULTS
  No significant difference between methods was found for the point estimates of six malaria indicators, education, caste or wealth of the survey participants (range of P: 0.06 to >0.99). A poor level of agreement occurred between the caste of the health worker used in household selection and the caste of the final participant, (Κ = 0.185), revealing little association between the two, and thereby indicating that caste was not a source of bias.
  
  
  CONCLUSIONS
  Although LBLM was not testable, a systematic last-birth approach was tested. If documented concerns of last-birth sampling are addressed, this new method could offer an acceptable alternative to segmentation in India. However, inter-state caste variation could affect this result. Therefore, additional assessment of last birth is required before wider implementation is recommended.
authors.affiliation: Department of International Health, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
authors.forename: Rosemary H
authors.initials: RH
authors.lastname: Davis
authors.affiliation: Department of International Health, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK jvaladez@liverpool.ac.uk.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Valadez
mesh_terms: D003710:Demography; D007722:Health Knowledge, Attitudes, Practice; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D008288:Malaria / Q000453:epidemiology*; D058996:Quality Improvement; D015203:Reproducibility of Results; D012494:Sampling Studies; D012923:Social Class
keywords: India; Indian health systems; KAP; LQAS; caste; community health; lot quality assurance sampling; reliability testing; sampling methodology; second-stage sampling; segmentation sampling; surveys