Appropriateness and execution challenges of three formal size estimation methods for high-risk populations in India

Abstract

Capture-recapture requires some knowledge of site location. It can be used as a community mobilization measure at the initiation of a programme. The multiplier method presumes the existence of high quality external data and requires care in selecting the appropriate multiplier. All size estimation methods require careful planning and a full understanding of population dynamics and limitations of data. Before selecting a size estimation method, one must be aware of the strengths, weaknesses and applicability of each method. Use of size estimation methods in large-scale programmes should be considered carefully with adequate importance given to planning and implementation.

Mapping and Size Estimation of High-Risk Populations in Large Scale HIV Prevention Programs: How Good is Good Enough?

“…These external surveys were expected to provide data on size through different established indirect methods. 5 The sizes from these estimations were similar to program estimates across different states and have been described and reported elsewhere. 35 Similar to the findings in this paper, the external surveys also suggest that mapping and size estimation processes improve with increased community involvement and program maturity.…”

Ecological analysis of the association between high-risk population parameters and HIV prevalence among pregnant women enrolled in sentinel surveillance in four southern India states

“…Furthermore, some segments of the FSW population are more difficult to capture than others (overt vs hidden FSWs), and the ability to capture them may vary from one site to the other. Second, there was no standardisation across Avahan districts for the methods used for size estimates 21. Third, even in the presence of valid estimates, FSW population size per se may not be a key variable for the heterosexual spread of HIV to the general population.…”

Evaluation design for large-scale HIV prevention programmes: the case of Avahan, the India AIDS initiative

“…In brief, a combination of extensive geographical and social mapping in urban and peri-urban areas with repeated, intensive Delphi techniques and focus group discussions with key informants (target populations, influencers) was used to arrive at district-wide denominators [73][74][75]. In addition, the evaluation partner responsible for running cross-sectional surveys among the target population was also charged with independently generating and validating size estimates with alternative methods (multiplier, capture-recapture, multistage sampling) in the subset of districts [13].…”

“…Other papers in the supplement present methodological and design strategies related to key components of the Avahan evaluation framework, results from a first round of surveys conducted among core and bridge populations as part of Avahan evaluation activities, and results from additional studies [7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”