|Meeting the Behavioural Data Collection Needs of National HIV/AIDS and STD Programmes (Implementing AIDS Prevention and Care Project - Joint United Nations Programme on HIV/AIDS - United States Agency for International Development, 1998, 41 p.)|
|4. What is needed to understand and track behaviour?|
What are they?
Behavioural surveys in the general population are cross-sectional household surveys in randomly selected samples of a population. They can be regional or community-based, and can address either the 15 to 49 age group or focus on youth ages 15 to 24. The interviewing is always done within the household. Population-based surveys should be repeated at regular intervals of several years to gain a picture of trends in behaviour over time.
What do they deliver, and what do they require?
Household surveys can provide a credible picture of the extent of risk behaviour in the general population and of the links between the general population and groups with higher-risk behaviour, such as sex workers or drug injectors. Understanding the magnitude of these links is essential to planning an effective national programme and directing resources. Should the links into the general population be limited, prevention resources can be concentrated largely in more vulnerable populations, with general population efforts being developed more gradually. Should these links be extensive, however, the potential for rapid HIV spread throughout the society is high, and resources should be mobilised to obtain broad population coverage in prevention programmes while still working intensively and extensively with vulnerable populations.
Household-based surveys are often logistically complex. However, many countries have experience with such surveys through national censuses and economic or health surveys. Sample flames and sampling expertise are often available through national statistical offices, local universities, or private firms. Indeed, existing survey programmes in these other areas may provide an opportunity to collect behavioural data relevant to HIV without setting up a separate survey structure.
Because participants in household surveys are randomly selected from the general population, selection bias is minimised provided that non-response is kept at a minimum. Sample sizes may be large, allowing frequencies of risk behaviour to be calculated for different age groups with small confidence intervals. In addition, standard procedures for sampling are easily replicated when the surveys are repeated.
In linking HIV sentinel data from key sites with behavioural data, it may be useful to oversample in areas surrounding key sentinel sites, provided the sampling area is defined in such a way as to select from the same source population that visits the sentinel site. Such oversampling can help ensure that sufficient behavioural data is collected in these areas to allow for informed interpretation of observed changes in HIV seroprevalence.
If the household-based survey includes data on HIV serostatus, it can establish links between risk behaviour and HIV infection at the individual level. It can also be invaluable in calibrating the results of sentinel serosurveillance among pregnant women (see also Second Generation Surveillance for HIV. The Next Decade and Beyond. Geneva: UNAIDS and WHO; 1998). Including data on HIV serostatus, however, considerably increases both the logistical complexity and the expense of a household-based survey. In some places the collection of HIV data - even if it is done using nonintrusive techniques such as saliva testing - may also increase refusals to participate in the survey. Thus, it is unlikely that such serostatus surveys can be tacked on to existing data collection efforts in reproductive health or other fields without substantially biasing the results. Such an exercise should be seen more as a research tool than a surveillance method.
Other points for consideration
Because they provide credible information on the general population, population-based surveys are an important advocacy tool. In several countries, national or regional surveys of sexual behaviour have set alarm bells ringing in the corridors of power and have prompted the establishment or strengthening of prevention activities countrywide (Table 1).
If household-based surveys collect internationally standardised indicators of risk behaviour, the information can be used to make intercountry comparisons. This must be done cautiously, however, because reporting bias may differ from country to country.
Household-based surveys are not good for tracking rare events or behaviours that are infrequent in the population. To get a statistically significant measure of change in behaviours not widely prevalent in some settings, such as injecting drug use or homosexuality, sample sizes in a household survey would have to be larger than is logistically or financially feasible.
Also, household-based surveys commonly underrepresent persons who are more difficult to contact at home. Individuals living in institutional settings, such as university students and military recruits, or mobile groups, such as males working away from home (e.g., miners, agricultural workers, or long-distance truck drivers), are usually not included in household-based general-population samples.
Experience has shown that national AIDS programmes encountered many difficulties when they tried to carry out population surveys themselves. Some national programmes had shortcomings in carrying out data management and analysis in a timely fashion. In some countries, the reports of behavioural survey data were not discussed, and their conclusions were not taken into account in the planning or redesign of prevention activities. In others, inadequate attention was paid to ensuring that neighbours or other family members could not inadvertently overhear respondents' answers to sensitive questions, producing seriously biased results. In addition, some people are reluctant to discuss sensitive matters such as sex and drug use with people they perceive as figures of authority in the state or community.
Finally, surveys of this type cannot provide the in-depth understanding of the factors influencing risk behaviour that is necessary for the design of prevention programs. While repeated household surveys can demonstrate trends in risk behaviour, they usually cannot explain those trends. Such explanations normally require qualitative follow-up of interesting findings using in-depth interviews, focus group discussions, anthropological observation, and other qualitative tools.