Behavioural Surveillance Surveys - The Wisdom of Whores

Geographic definitions of survey domains
Once operational definitions have been
agreed upon survey designers need to
determine to what geographic area they wish
to be able to extrapolate results. For example,
surveys conducted exclusively among school
children in urban areas cannot be extrapolated
to school children in rural areas. Ideally,
behavioral data for specific sub-populations
should be monitored on a national basis, with
sufficient sample sizes to allow for separate
estimates for different regions. Although
comparisons across regions, cultures and
countries must be made with extreme caution,
this type of behavioral data can help explain
differences in levels of HIV infection between
one region and another, and help to identify
local prevention needs. Regardless of whether
coverage is national, regional, or only for a
subset of regions, it is important to recognize
that the generalizability of survey findings is
limited to those areas included in the universe
for the survey effort.
Many factors (including cost, feasibility
and political expediency) will influence the
geographic coverage of BSS. One important
consideration for managers of national HIV
surveillance efforts should be the distribution
of HIV sero-surveillance efforts. The principles
of second generation surveillance dictate that
behavioral and serological data be used in
conjunction to explain trends in the epidemic.
It is not possible to do this with confidence
unless the data are drawn from the same
source populations. Behavioral data collected
from married women in the capital city will do
nothing to explain sentinel surveillance data
recorded among women at antenatal clinics in
rural areas. It is therefore advisable to try to
conduct BSS in the same geographic area as HIV
sero-surveillance for a given sub-population.
Indeed where sero-surveillance efforts use
population-based sampling approaches for
a given hard-to-reach population, the same
sampling frame and sampling design can be
used for both HIV surveillance and behavioral
surveillance. For reasons given in the
discussion of choice of respondent groups,
however, it is not advisable to collect
behavioral information and biological specimens
from the same individuals.
Each geographic catchment area is, properly
speaking, considered a separate sampling
universe. However, if data collection is
spread out across the country and the data
are weighted appropriately, it is sometimes
possible to derive national estimates of
behavioral indicators.
Step 6 : Site Selection and
Mapping
After rapid assessment has shown that a
sub-population can feasibly be accessed in
large enough numbers to produce meaningful
data, the universe and domains have been
identified and criteria for the inclusion of
potential respondents have been set, a more
thorough process of mapping and selection
of sampling points can begin.
Behavioral data collection which focuses
on populations with higher levels of risk
behavior must identify points where
populations are accessible in a comprehensive
way if representative data are to be collected.
This generally involves a mapping of sites
where the behaviors take place, such as
brothels, shooting galleries, gay bars, and
cruising areas, together with an estimate of
the number of individuals associated with
each site. More information on this process
is provided in Chapter 4.
B EHAV I OR A L S U R V EI L L A NC E SURV EY S CHAPTER 2
17