Behavioural Surveillance Surveys - The Wisdom of Whores

Figure 6 : Steps in using the segmentation method to choose sample households
1. Calculate the number of segments to be created. Divide the number of households
recorded in the last census by the target segment size. The result will be the number of
segments to be created in the field. For example, if the last census indicated that there were
250 households in the cluster and the target segment size was 40 households, 6 segments
would need to be created for that cluster. (Note : in performing this calculation, decimal
numbers of segments should be rounded to the nearest whole number.)
2. Update the cluster map. Using a map of the cluster, verify/update the external boundaries
of the cluster and enter any internal features that may be useful for dividing the cluster into
easily recognizable segments.
3. Count and indicate the location of households located in the cluster on the map.
This is intended to be a quick operation undertaken so that the cluster can be divided into
segments with approximately equal numbers of households.
4. Based upon the cluster map, divide the cluster into equal-sized segments.
The number of segments to be used is the number determined in Step 1 above.
5. Choose one segment at random.
6. Interview all households located within the boundaries of the randomly-chosen segment.
An illustrative application of the “segmentation” method is provided in Figure 7.
Figure 7 : Example of a hypothetical cluster that has been divided into six segments
Source: United Nations Children’s Fund. 1995. Monitoring Progress Toward the Goals of the World Summit
for Children: A Practical Handbook for Multiple-Indicator Surveys. New York: UNICEF.
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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