Project: SAPIENs – A tool to conduct Small Area Population Evaluations


The project has developed a tool and guidance, the SAPIENS resources, which allows neglected tropical disease (NTD) programmes to evaluate and, if necessary, improve the quality of small area population data, which in turn can improve drug allocation and increase accuracy of reported coverage values. As interest in more focal treatment increases, accurate population data for small areas will be vital for programme planning evaluation, this is where SAPIENS will be most beneficial.

Why is this important?

In the absence of accurate and up-to-date population sources, countries commonly apply annual population growth rates to national census population data either regionally or nationally to project annual population estimates.

Accurate population data, disaggregated by age groups and sex across all administrative units are necessary to plan, implement, and evaluate mass drug administration (MDA). A lack of suitable population data for implementation units (IU) affects efficiency in all stages of an NTD programme.

A lack of suitable population data for IUs affects efficiency in all stages of an NTD programme. In terms of planning, it may result in programmes making an inaccurate WHO Joint request for selected PC Medicine submissions. During implementation, programmes may face logistical challenges resulting from imprecise drug allocations (surplus or scarcity of drugs); whilst the use of unreliable programmatic metrics to assess programmes’ success (e.g., coverage denominators) can compromise monitoring and evaluation as well as major reporting activities (eg., inaccurate Joint Reporting Form to the WHO).

Presently, there are no standardised tools or guidance available for NTD programme managers to evaluate population data used by an NTD programme. SAPIENs aims to tackle the gap through the development of a method, the SAPIENs Guidance Document, to aid NTD programme managers to understand and address concerns with official population data.


Recent advances in geospatial and machine learning methods, and increased availability of high-quality aerial and satellite imagery, have enabled significant developments in population modelling, improving the accuracy of the subsequent modelled population estimates. The top-down and bottom-up models produced by the research group WorldPop, University of Southampton, are prime examples of such innovations. These models combine survey-based population data with high quality satellite imagery to create 100 x 100m gridded population estimates. These innovative methods for population modelling have opened new information sources for the evaluation of population data used by NTD programmes through the SAPIENs Guidance.


Key Details

  • Organisation: SCI Foundation
  • Geography: Worldwide (Case study: DRC)
  • Timeline: 6th July 2020 – 30th October 2020
  • Budget: £24,702.45


SAPIENs was a vital first step to understand the usability of the WorldPop models for NTD programme managers, providing opportunity to assess population data used by the NTD programme. SAPIENs investigated these novel methods to model population estimates and created an easy-to-use Population Review Workbook and a complimentary SAPIENs Guidance Document (jointly referred to as the SAPIENs resources) which enabled teams to identify issues in NTD programme population data. It is hoped that the SAPIENs resources can give NTD programmes the ability to challenge and/or justify the population data they use, whilst providing an opportunity for conversations and actions towards improving population figures. Ultimately, working to support all eligible individuals to receive the treatment they require.

Future Learning

A next step by the SAPIENs team is to firstly trial the SAPIENs resources with an NTD programme manager or data manager. This capacity building on SAPIENs resources would allow for further feedback to be incorporated into the SAPIENs Guidance Document and Population Review Workbook, to further its usability.

SCI Foundation is hoping to trial the integration of micro censuses, used in bottom-up models, alongside regular NTD monitoring and evaluation surveys, and investigate the additional cost required to do so. This would provide the opportunity to gather the micro census input data required to run the bottom-up model, as well as for the frequent use alongside NTD programmes for increased accuracy population data in the most cost-effective way possible.

Further SAPIENs projects could specifically attempt to aid countries in targeting specific at-risk groups, as further modelling could be trialled to evaluate specific at-risk populations, such as, non-attending school aged children and young women, aged 16 to 25, at risk of female genital schistosomiasis (FGS). This research would aid NTD programmes to further refine their control programmes for schistosomiasis (SCH) ensuring coverage of all necessary populations, then, where data available, informing SCH elimination strategies.

Acknowledgement: Photo provided by SCI Foundation