Behavioural Surveillance Surveys - The Wisdom of Whores

In Figure 3, clusters were chosen by
following the procedure outlined in Chapter 4,
Figure 2, rounding the cluster selection
number down if the decimal was below
0.5, and rounding up if the decimal was above
0.5. In this way, 34 time-location clusters
were systematically chosen with equal
probability.
How to organize the field work
There are many different ways that the
fieldwork can be organized. Here is one
suggested option.
Since there are a total of 34 clusters to be
completed in 3 weeks, the survey manager
could plan to have the interviewers complete
approximately 12 clusters during the first
week, 12 clusters during the second week,
and the remaining 10 clusters during the third
week. If there were three teams each doing
four clusters per week, it should be feasible to
complete the work in a three-week time-frame.
The first 12 clusters would be completed
during the first week. From Figure 3, the first
12 cluster that were selected are the following:
Site 1 on a weekday
Site 2 on a weekday
Site 2 on a weekend night
Site 3 on a weeknight
Site 4 on a weekday
Site 4 on a weekend night
Site 5 on a weekend night
Site 6 on a weeknight
Site 7 on a weekday
Site 7 on a weekend night
Site 8 on a weeknight
Site 9 on a weeknight
If a weekday or weeknight is chosen, then
the specific day of the week on which the
team should visit the site can be randomly
chosen from among the five weekdays
(Mon-Fri) during the first week of the survey.
If a weekend is chosen, then either Friday or
Saturday night can be randomly chosen. The
two-hour time-frame should be agreed upon
in advance, and be based upon information
about what time the women are most likely to
be at the site, and also be available for a 30-45
minute interview. The goal would be to
complete 10 interviews from each timelocation
cluster, being careful to keep track
of the total number of women who come into
contact with the site during the two-hour
time-frame. The team would also need to
record the number of refusals and the number
of duplicates, from among those women who
were selected to participate. Even if the 10
interviews were completed before the two
hour time-frame was complete, it would still
be necessary for someone to remain at the site
for the full two-hour time period, so as to
count the total number of women who came
in contact with the site during the specified
time period. This information would then be
used as the measure of size for the cluster for
calculation of sampling probabilities.
A similar procedure would be used during
the second and third week of the survey,
to complete the 34 time-location clusters.
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A PPEN DI X 3 B EHAV I OR A L SURV EI L L A NC E S U R V EY S