Reliability and validity checks will be conducted to assess the quality of the quantitative data [36]. Data analysis will be conducted using statistical software - eg: STATA and SAS - and mathematical models of HIV incidence, which are based on underlying biomedical, behavioural and demographic determinants of HIV infections [37,38]. Statistical analyses will include tests for the significance of differences arising between paired intervention and control clusters [39,40] and tests for impact of contacts with the intervention programme and other possible determinants on changes in reported behaviour. The impact of the HIV epidemic on mortality will be monitored using longitudinal survey data and official vital registration records. Impact on fertility will be assessed by comparing birth rates among infected and uninfected individuals, controlling for other key determinants including age, education, religion and history of STDs. Crude birth rates, crude death rates and levels of natural population increase will be estimated from the survey data and the trends evaluated [12]. Coverage and impact of care/support interventions will be investigated. HIV prevalence estimated from the population-based survey will be compared with estimates from women attending antenatal clinics to assess the representativeness of the latter. Adjustments will be made in data analysis for the matched-pair design of the study. Data from the study will be used to evaluate new methods for estimating incidence from cross-sectional HIV prevalence surveys [27].