Quantitative data will be collected on the intervention trial outcome measures summarized above, principally through the two-round survey. A cohort of participants for this survey will be recruited in a household census within each of the twelve study areas. The second round of the study will be conducted two years after the first visit in each area and will involve a repeat household census and further detailed interviews with the original participants. The population-based survey will also provide data on process indicators, including measures of contact with the intervention programme - eg: numbers of meetings attended and visits received from programme personnel - and utilization of programme services - eg: free condoms, revolving loans, care support, STD diagnosis and treatment - and other potential determinants of key outcomes, including socio-economic and demographic factors, and personal experience of HIV-related morbidity and mortality. Data will be collected on demographic indicators - eg: age- and gender-specific mortality, recent fertility, orphanhood and household composition - in the household and individual interviews, using standard demographic methods [30,31]. Quantitative data will also be collected on HIV prevalence at antenatal clinics, so that the representativeness of data from this source can be evaluated. Qualitative data on sexual and health-seeking behaviour and obstacles to behaviour change will be collected in focus-group discussions, pocket-chart voting sessions and key-informant interviews [32,33] and employed to aid questionnaire design and validation and in interpretation of statistical results. These methods were used successfully in our previous study [7]. However, to strengthen this aspect of the current proposal, additional input on the design and implementation of appropriate ethnographic methods will be received from a collaborator from the LSE (Dr. Campbell).