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Small Area Population Evaluations (SAPIENs)

SAPIENs: A tool to conduct Small Area Population Evaluations. A method to evaluate and tackle concerns with official population data within NTD programmes

SAPIENs: A tool to conduct small area population evaluations.

A method to evaluate and tackle concerns with official population data within NTD programmes


Countries: Worldwide

Implementing partners: The Ascend West and Central Innovation Fund (provided by UK Aid).

Timescale: 6 July 2020 – 30 October 2020

Neglected Tropical Disease (NTD) programmes use population data to plan, implement and evaluate mass drug administrations (MDA). Population data at the disposal of NTD programmes is often inaccurate or outdated due to the irregular completion of national censuses. A lack of access to accurate population data affects efficiency in all stages of an MDA campaign; for example, it can result in too many or too little drugs delivered to areas of need. Similarly, inaccurate calculations of MDA coverage can affect a Ministries of Health’s (MoH) progress towards control and elimination of NTDs.

Although inaccuracies in population data may be known by a programme, presently, there are no standardised tools or guidance available for NTD Programme Managers to evaluate population data used by an NTD programme.

Unlimit Health has been working on SAPIENs to evaluate small area populations, and tackle the challenges encountered with population data.

Addressing the unmet need

The focus of the SAPIENs project was to investigate population modelling and evaluate their use and implementation in NTD Programmes; the aim being to create a tool which would allow NTD Programme Managers to analyse and address concerns with official population data.

Recent advances in high-quality satellite imagery (alike to that used for Google Maps) and modelling has led to the development of innovative solutions to get accurate population estimates, such as the WorldPop top-down and bottom-up models.

SAPIENs has, for the first time, provided an opportunity to understand WorldPop’s novel modelled population data in the context of NTDs. Using this newfound knowledge to create a comprehensive methodology for NTD Programme Managers to assess and possibly solve issues using innovative WorldPop modelled population data.

Map of Kinshasa showing population estimates

Bottom-up population estimates of DRC’s capital city, Kinshasa, and the surrounding area. Colours represent the population per 100m by 100m squares (all age-sex groups) with the lightest yellow showing areas of 1-25 people, and the darkest red 600-816 people. As the colour darkens from yellow, to orange, to red, the population per square increases. Screenshot taken from: All data and intellectual property belong to WorldPop, University of Southampton. Source data: WorldPop Open Population Repository (WOPR), Source code: wopr R package v0.4.6.

SAPIENs programme objectives

  • Develop a clear and cost-effective method for NTD Programme Managers to assess population data used by an NTD Programme when planning and evaluating MDAs
  • Provide guidance on how to introduce modelled population estimates and findings from the SAPIENs method to policy makers and/or decision makers
  • With pilot data, complete a comparison of population data used by an NTD programme for implementation and reporting to population estimates from WorldPop models, in hopes to provide key evidence and learnings towards the use and value of the method created through SAPIENs

Achievements of the project so far

  • SAPIENs has provided key evidence needed to address the problem of inaccurate population data used for NTD Programmes and clear recommendations for next steps moving forward
  • SAPIENs successfully created a tool (Population Review Workbook) and complimentary guidance (SAPIENs Guidance Document) to provide NTD Programme Managers with an option to identify and evaluate population data where there is uncertainty in its reliability or accuracy
  • It is hoped that the SAPIENs resources can give NTD Programmes the tools 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 research

Now a methodology has been developed, and the capacity and data required for models reviewed, the next step is to implement and discuss the SAPIENs resources and findings with NTD Programme Managers to continuously work to improve the SAPIENs tool and guidance.

SAPIENS Guidance Document and Population Review Tools