THPE117
Direct and Indirect Methods for Estimating the Size of the Female Sex
Worker Population in Addis Ababa, Ethiopia.
Authors: Habtamu Tamene1, Belayneh Dagnew1, Mekuria Yilma1, Woldemariam Girma1, Amy
Kate Herman-Roloff2, Hayden Hawry1, Daniel Tsegaye1. 1 PSI/E, 2CDC/Z
RESULTS
BACKGROUND
• Further analysis was done at 962 worksites (36% of the total number of
worksites) that all three methods were used to estimate the FSW
population size.
Figure 1: Estimates of FSW Population: Direct vs Indirect Method
•
Population Services International Ethiopia (PSI/E), in collaboration with
partner organizations, has been implementing a national HIV prevention
project targeted at female sex workers (FSWs) and their client. However,
there is little information on size and location of FSWs in Ethiopia.
•
It is important to estimate the size of key populations, including FSWs *,
when planning effective, targeted interventions.
•
This study used three different approaches to provide broader insights
into estimating the size of FSW populations in Addis Ababa Ethiopia in
2012 and the comparative advantages of each method.
METHODS
All potential FSW worksites were mapped with the support of peer educators
and local implementing partners in ten sub cities of Addis Ababa. FSWs
Worksites with at least one FSW were identified; and three different methods
were applied to estimate the size of the FSW population:
Venues of FSWs by type of worksite
Method
Direct
Indirect
Establishment
Street
Home
Total
Census
831
131
1697
2659
CaptureRecapture
831
131
KIInterview
831
131
• The direct estimate (capture recapture estimates of size of
FSWs in establishments and streets, and census estimates of
the FSWs size of home based FSWs) gave an aggregate
estimate of 11632 (95% CI, 11502-11762) FSWs population in
Addis Ababa.
• The indirect estimate of FSWs population in Addis Ababa was
11532 that is within the confidence interval of the direct
estimate.
Figure 2: Estimates of Direct Vs Indirect Method by FSWs
Venue Type
962
1697
In the Ethiopian context, FSWs are categorized into three based on the place
where they solicit their clients:
• Analysis was conducted in SPSS V17.
PSI■■
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PSI.ORG
Indirect method estimates of FSW population size do not differ
significantly from direct method estimates.
• Indirect and direct method estimates of FSW population size are closer for
relatively stable FSW categories, such as home-based FSWs, than for
relatively unstable FSW categories, such as establishment or street
FSWs.
• The indirect method approach (KI interview) has less psychological effects
on study participants than the direct method approach because direct
observation of study subjects is not required for the former.
• PSI/E used the finding as evidence to apply the indirect method for FSWs
size estimation in other study towns.
• Home based: FSWs who solicit clients at their place of residence. Often
times these women also sell local liquor such as Araki, Tella,…
• Establishment based: FSWs who use establishments such as hotels, bars,
nightclubs, groceries and restaurants to make contact with and solicit
clients.
• Street based: FSWs who solicit clients on the street or in public places such
as bus stands, or market places
• Semi-structured interviews were conducted with key informants (FSWs
and worksite staff/owners) at each FSW worksite.
•
• Considering the substantially higher costs of using direct methods to
estimate the size of FSWs population, the use of indirect methods is
recommended for home based FSWs and other relatively stable
populations.
2659
• Capture-recapture method was used to estimate the size of the FSW
population at FSW worksites with high mobility including establishments
and streets.
• Census and key informant interview methods were used at all FSW
worksites including homes, establishments, and streets.
CONCLUSIONS
Literature cited
*Save
the Children, USA, 2010, Baseline Survey among Most at Risk
Populations in Ethiopia
• The deviation between direct and indirect estimates of FSW population
size was smallest for home based FSWs.
Contact
• Direct estimates of FSWs population size were greater than indirect
estimates of population size for establishment based FSWs and street
based FSWs.
• For home based FSW, the indirect estimate of population size was greater
than the direct estimate of population size.
For any further information related with this study please contact Mr. Habtamu
Tamene, email : [email protected]