Evidence Action's Deworm the World Initiative — Nigeria, Pakistan, and Kenya (January 2023)

Note: This page summarizes the rationale behind a GiveWell-recommended grant to Evidence Action's Deworm the World. Deworm the World staff reviewed this page prior to publication.


In January 2023, GiveWell made a $5.2 million grant to Evidence Action's Deworm the World. This grant was disbursed alongside a separate $2.5 million grant to Deworm the World to support deworming in India. Together, these grants were funded by approximately $3.4 million in donations to the All Grants Fund between October and December 2022, approximately $2.9 million from unrestricted donations which have been designated by the GiveWell board for making grants, approximately $0.2 million in donations collected by GiveWell for Deworm the World in Q3 and Q4 2022, approximately $0.8 million in donations to GiveWell's Vanguard Charitable account for the All Grants Fund in 2022, and approximately $0.4 million in donations to the All Grants Fund through Giving What We Can in 2022. This grant will continue support for deworming programs that GiveWell grants have previously supported, in Nigeria ($3.4 million), Pakistan ($1.0 million) and Kenya ($0.9 million), for one additional year (through 2025).

We recommended this grant because we believe that the work that the grant will support will be cost-effective. Deworming is among the most cost-effective programs we know of, in certain locations. The need for deworming appears to be high in the areas where Deworm the World expects to use this grant. We have followed Deworm the World's work since 2012 and believe that it is well-positioned to support this work.

Published: April 2023

Table of Contents

Planned activities and budget

This grant will extend support for the majority of GiveWell-supported ongoing programs through 2025. Our February 2022 grant to Deworm the World supported these programs through 2024. This grant does not renew support for regions in Pakistan outside of Khyber Pakhtunkhwa. This decision is discussed further here. The grant size is based on our estimates of the following funding gaps:1

  • $3.4 million for five states in Nigeria (Ogun state, Oyo state, Rivers state, Lagos state, Cross River state)2
  • $1.0 million for Khyber Pakhtunkhwa in Pakistan
  • $0.9 million for Kenya

See here for a discussion of how Deworm the World has spent past funding by spending category. We expect this grant to be spent similarly.

The case for the grant

  • We estimate that this grant will meet our bar for cost-effectiveness. More below.
  • We believe that it is unlikely that another funder will cover these costs. More below.
  • Deworm the World has a track record of supporting successful deworming programs.3 More in our review of Deworm the World.


Based on our cost-effectiveness analysis of the program, we believe it is in the range of cost-effectiveness of programs we expect to direct funding to, as of January 2023 (10 or more times as cost-effective as unconditional cash transfers, or "10x" for short).4 Our overall cost-effectiveness estimate for this grant (based on weighting each geography's cost-effectiveness by the amount of funding allotted) is approximately 16 times as cost-effective as unconditional cash transfers, or "16x."5 Our cost-effectiveness estimates for Deworm the World's program in each geography included in the grant are below.

Program Cost-effectiveness6 ​​
Ogun state, Nigeria 14x
Oyo state, Nigeria 15x
Rivers state, Nigeria 11x
Lagos state, Nigeria 9x
Cross River state, Nigeria 11x
Khyber Pakhtunkhwa, Pakistan 7x
Kenya 35x

We extended funding for an additional year in two geographies despite estimating cost-effectiveness less than 10x. These geographies represent approximately 20% of the total grant size.7 We have discussed with Deworm the World that we may not continue to fund these geographies in future grants, barring changes to our cost-effectiveness estimates or our cost-effectiveness bar for funding decisions.

  • Lagos state, Nigeria: Deworm the World's program in this state in 2025 will be primarily supported by non-GiveWell funds. We decided to provide $0.06 million in this grant to fill the remaining funding gap in Lagos because cost-effectiveness is near our current 10x bar.
  • Khyber Pakhtunkhwa, Pakistan (KP): GiveWell previously supported Deworm the World's program operating across Pakistan. At the time of our last grant to Deworm the World in February 2022, we estimated the program's cost-effectiveness to be approximately 5x at the country level, and the program was funded out of a limited pool of GiveWell funding for programs between 5x and 8x. Our funding bar is now 10x, and we have not renewed our support for most regions in Pakistan due to estimated cost-effectiveness below 10x at the regional level (1-5x).8 We decided to continue supporting KP because it was the most cost-effective region in Pakistan at 7x, we may be underestimating worm burden in Pakistan, and doing so alleviates some of the fundraising pressure on Deworm the World (which hopes to fundraise for the rest of the program). We believe worm burden may be underestimated due to data limitations related to 1) using worm burden data at the ecological zone level9 while Deworm the World treats at the district level,10 and 2) using worm burden data that was collected after some deworming had occurred (i.e., may not represent a reasonable estimate of what worm burden would be if GiveWell funding ended).11 As a result, it is plausible we may estimate KP's cost-effectiveness to be 10x or higher in the future. We may also estimate that other regions in Pakistan are 10x or higher, though this seems less likely given our current estimates (less than 5x).

Our cost-effectiveness analysis for this grant is based on the same structure as our model for other deworming grants. While investigating this grant, we updated parameters within that model to use inputs specific to this funding gap. Below, we highlight parameters that vary for different funding gaps and have a substantial impact on our headline cost-effectiveness figures:

  • Worm burden: For every deworming grant, we ask the potential grantee to provide data on the prevalence and/or intensity of infections with each species of schistosomiasis and soil-transmitted helminths in the locations where they would support deworming. We prefer to use data on the prevalence of moderate-intensity infections and of heavy-intensity infections for each species. When this isn't available, we use average intensity of infection or prevalence of any infection. We then apply an adjustment to our cost-effectiveness estimates of deworming programs to account for differences between the prevalence and intensity of worm infections in the geographies targeted by our deworming grantees and the prevalence and intensity of worm infections among the population studied in Miguel and Kremer 2004, the randomized controlled trial (RCT) on which we base our estimate of deworming's impact on consumption. Worm burden varies significantly across the geographies supported by this grant, and consequently so does this adjustment: from 5% of the level during the RCT to 21%.12
  • Cost per child dewormed: Our cost per child estimates for each geography can be seen in our cost-effectiveness analysis here and range from $0.65 per child dewormed in Kenya to $1.52 per child dewormed in Ogun, Nigeria.13 For three states in Nigeria (Cross River, Ogun, and Rivers) we did not have enough reliable new program information to update our estimates for the programs.14 Updates to cost per child in Kenya, Oyo state, and Lagos state increased cost-effectiveness by an average of approximately 10%. Updates to cost per child in Pakistan decreased cost-effectiveness by approximately 17%.15

We made two additional updates to our cost-effectiveness analysis which affected our final cost-effectiveness estimates:

  • We increased our adjustment for "misappropriation without monitoring results" from 1% to 5% for Nigeria here in the cost-effectiveness analysis. Select states in Nigeria conduct two rounds of deworming per year. Given that Deworm the World typically only conducts coverage surveys for 1 of these 2 annual rounds of deworming,16 we have somewhat lower confidence that the coverage results we receive accurately reflect the entirety of the program.
  • We incorporated an adjustment to our cost-effectiveness analysis to account for the possible decay of deworming benefits over time, which decreased cost-effectiveness by approximately 10%. See here to read more about this update.

Funding landscape

For this grant, we considered what we know about the funding landscape in each of the countries, combining historical and new knowledge:

  • Nigeria: We wrote about the impact of the UK government ending its support for these programs in 2021 in our February 2022 grant page. At that time, we were aware that the Bill and Melinda Gates Foundation (BMGF), the Children's Investment Fund Foundation (CIFF), and ELMA Philanthropies were planning to provide additional neglected tropical disease (NTD) funding to help address the gap left by the UK government.17 However, we were not aware where or for what activities this funding would be deployed. Since then, we've learned that this funding consortium (ARISE) is focusing their $65 million Phase 2 NTD funding commitment on Senegal, Ethiopia, South Sudan, Burkina Faso, and Kenya.18 Further, our current understanding based on conversations with other funders is that funding gaps remain in Nigeria.
  • Kenya: As we wrote in our February 2022 grant page, GiveWell has been supporting the deworming program in Kenya for several years so we haven't been able to observe whether this funding gap would be a priority for other funders if we were not funding it. We are aware of several other funders supporting NTD programs in Kenya, including the BMGF, CIFF, and ELMA Philanthropies funding consortium mentioned above.19 Therefore, it is plausible that GiveWell funding is crowding out other funders. However, even a moderately substantial adjustment for crowding out other philanthropic funding in our cost-effectiveness analysis would be unlikely to bring Kenya below 10x, given our high cost-effectiveness estimate of approximately 35x.
  • Pakistan: As we wrote in our February 2022 grant page, we are not aware of other potential major sources of funding for deworming in Pakistan and this continues to be our understanding.

As a result, we hypothesize that the probability of crowding out other philanthropic funding in these countries is relatively low.

We also believe the probability of crowding out non-GiveWell Deworm the World funding is relatively low. Deworm the World has internally allocated approximately $4 million of non-GiveWell directed funds to several programs in 2023-2025, including some we estimate to have cost-effectiveness below 10x.20 However, based on discussions with Deworm the World, we believe that the allocation of non-GiveWell funds is reasonably aligned with how Deworm the World would allocate these funds if GiveWell did not make further grants to Deworm the World. We are also cognizant of the mis-incentive that could be created (i.e., an incentive not to fundraise) if GiveWell was to consider all use of non-GiveWell funds below our cost-effectiveness bar to be crowding out other funding.

Risks and reservations

  • As mentioned above, we have not incorporated an adjustment for crowding out of other philanthropic funding in our cost-effectiveness analysis. This may lead us to overestimate cost-effectiveness. We hypothesize that the risk is highest in Kenya, given that we are aware of multiple other NTD funders supporting work in Kenya.21 As GiveWell has been providing support for several years in both Kenya and Nigeria, it is also more difficult to assess the likelihood of another funder stepping in if GiveWell funding was not available. We ultimately did not incorporate an adjustment as we believe the risk of crowding out other funders is relatively low and unlikely to change our funding decision. However, it is possible that further analysis would change this perspective.
  • There is a risk that our decision not to renew support for the majority of Pakistan could be the result of underestimating cost-effectiveness, as discussed above, or that it could have unintended consequences. We believe we have explored these potential consequences relatively comprehensively in conversation with Deworm the World, including the following:22
    • A missed opportunity to consider a more targeted treatment approach that could be 10x or above: We concluded in discussion with Deworm the World that this may be too logistically challenging within Deworm the World's current model.
    • The possibility that cost per child in KP could increase if deworming programs do not continue in the rest of Pakistan: Deworm the World does not expect there to be a substantial cost per child increase, in part because KP represents approximately 50% of the country program and fixed costs are primarily at the province rather than national level.23
    • Potential impact on Deworm the World's relationship with the Pakistan government if deworming programs do not continue in the rest of Pakistan: Deworm the World noted that—while it hopes to fundraise for the rest of Pakistan—if it is unable to operate in regions outside of KP, this could negatively impact the KP program due to loss of momentum at the national level.
  • WHO recently updated its treatment guidelines for schistosomiasis.24 Our understanding based on conversations with grantees is that many countries are currently re-evaluating or planning to reevaluate their deworming strategies and gradually move towards these updated guidelines. This includes moving to more targeted sub-district treatment and expanding target populations beyond school-age children.25 It's not clear to us how that will affect funding needs and cost-effectiveness of deworming programs in these locations over the next few years. Changes could result in us having over or underfunded these programs, and could also make it more difficult to evaluate cost-effectiveness in the future.
  • Lastly, our cost-effectiveness model for deworming relies primarily on a single study and associated follow up studies which suggest that deworming increases future income. Please see our deworming intervention report for more discussion of this.

Plans for follow up

Deworm the World provides annual updates on program monitoring, results of coverage validation surveys, and spending for each program it supports. It also shares informal updates through email and monthly update calls.

Internal forecasts

Confidence Prediction​​ By time​​
55% All Pakistani administrative units26 (except for Gilgit-Baltistan) remain less than or equal to 10x at the end of our next grant investigation. January 2024
10% We learn that another funder had been considering supporting deworming in one of the geographies covered by this grant. June 2023
20% Lagos state, Nigeria is ≥10x at the end of our next grant investigation. January 2024
70% Ogun state, Nigeria is ≥10x at the end of our next grant investigation. January 2024
60% Deworm the World raises sufficient funds to fill more than 75% of the current Pakistan funding gap in 2025 ($1.58 million). December 2024

Our process

Our process for this grant relied heavily on (a) our prior work on modeling Deworm the World's cost-effectiveness, and (b) our following Deworm the World's work on the deworming programs we have funded since 2013, including frequent discussions with Deworm the World and reports on program monitoring, coverage achieved, and funding spent. For this particular grant, we:

  • Updated our cost-effectiveness analyses as described above;
  • Reviewed the latest coverage evaluation survey reports and latest spending and treatment data (through the 2021 program year);
  • Analyzed Deworm the World's room for more funding request; and
  • Spoke with other funders supporting NTD programs about the broader deworming funding landscape.

For internal review, a Program Officer who was not otherwise involved in the grant investigation gave feedback on the plan for investigating the grant. A Senior Program Associate and a Senior Research Associate reviewed the case for making the grant and gave feedback prior to final grant approval by a Senior Program Officer.


Document Source
Evidence Action, "Pakistan’s First Nationwide STH Survey: Determining the Intensity and Prevalence of Worm Infections," 2017 Source (archive)
GiveWell, "Combination Deworming (Mass Drug Administration Targeting Both Schistosomiasis and Soil-Transmitted Helminths)," 2022 Source
GiveWell, "Evidence Action's Deworm the World Initiative – August 2022 version" Source
GiveWell, "Evidence Action's Deworm the World Initiative — Pakistan, Nigeria, and Kenya (February 2022)" Source
GiveWell, "GiveDirectly – November 2020 version" Source
GiveWell, "GiveWell's Cost-Effectiveness Analyses," 2023 Source
GiveWell, "Sightsavers — Support for Deworming in Kaduna, Zamfara, Niger, Kano, Adamawa, and Katsina in 2021-2023 (October 2021)" Source
GiveWell, "Summary of GiveWell's 2020 Worm Burden Adjustment Model" Source
GiveWell, 2023 GiveWell cost-effectiveness analysis — version 2 Source
GiveWell, 2023 V1 to 2023 V2 CEA change tracker Source
GiveWell, 2023 Worm burden adjustment model Source
GiveWell, Cost-effectiveness of January 2023 DtW Renewal Grant, 2023 Source
GiveWell, Deworming decay adjustment, 2023 Source
GiveWell, GiveWell's estimates of Deworm the World's cost per child dewormed per year, 2022 Source
GiveWell, Room for more funding analysis for Deworm the World, 2022 Source
Interactive Research and Development, Baseline Survey Report of Soil-Transmitted Helminths Prevalence in Pakistan, April 2017 Source (archive)
Miguel and Kremer 2004 Source
WHO, "WHO guideline on control and elimination of human schistosomiasis," February 2022 Source (archive)
  • 1

  • 2

    This includes $0.6 million for an impact assessment in Cross River state in 2023.

  • 3

    "Deworm the World sends monitors to schools during and, for most distributions, after deworming to determine whether the programs it supports have reached a large proportion of children targeted. We have reviewed data from each of its major programs, which overall indicate strong results." GiveWell, "Evidence Action's Deworm the World Initiative – August 2022 version".

  • 4

    Note that a) our cost-effectiveness analyses are simplified models that are highly uncertain, and b) our cost-effectiveness threshold for directing funding to programs changes periodically. As of January 2023, it is 10 times as cost-effective as unconditional cash transfers. See GiveWell’s Cost-Effectiveness Analyses for more information about how we use cost-effectiveness estimates in our grantmaking.

  • 5

    See calculation here.

  • 6
    • We use GiveDirectly's unconditional cash transfers as a benchmark for comparing the cost-effectiveness of different funding gaps. Thus, if we estimate that a funding gap is "10x" this means we estimate it to be ten times as cost-effective as unconditional cash transfers.
    • See cost-effectiveness calculations here.

  • 7
    • See funding amounts for each geography here.
    • $0.98 million (KP) + $0.06 million (Lagos state) = $1.04 million
      $1.04 million/$5.20 million (total grant) = .2
      $1.04 million is 20% of the $5.20 million grant

  • 8

    One province (Gilgit Baltistan) is greater than 10x but represents a small portion of the overall Pakistan program. We have low confidence in our cost-effectiveness estimate for Gilgit Baltistan given limited data on worm burden and cost per child.

  • 9

    "While schools from all the administrative regions of Pakistan were not included in the survey, all ecological zones of Pakistan were represented. This sampling procedure followed WHO-recommended methodology. Using this methodology, epidemiological data gathered from schools spread across each ecological zone provides representative information for the whole country." Evidence Action, "Pakistan’s First Nationwide STH Survey: Determining the Intensity and Prevalence of Worm Infections," 2017

  • 10

    Deworm the World, conversation with GiveWell, December 5, 2022 (unpublished).

  • 11
    • Deworm the World, conversation with GiveWell, January 17, 2023 (unpublished).
    • While this data is not ideal, it is from the first nationwide survey of STH (soil-transmitted helminths) conducted in Pakistan and is currently the primary source for worm burden data in Pakistan.

  • 12Worm burden adjustments are here in our cost-effectiveness analysis. This is the supplemental sheet these estimates are pulled from.
  • 13See here for our cost per child analysis.
  • 14Due to the impact of the COVID-19 pandemic on these programs.
  • 15See changes in cost-effectiveness here.
  • 16Deworm the World, answers to GiveWell's monitoring questions, November 2022 (unpublished).
  • 17"Deworming in these six [Nigerian] states was previously funded by the UK's Foreign, Commonwealth & Development Office (FCDO) under the Accelerating the Sustainable Control and Elimination of Neglected Tropical Diseases (ASCEND) program. FCDO ended the ASCEND program in 2021, 8-12 months earlier than expected, citing 'a challenging financial climate as a result of COVID.'

    Children's Investment Fund Foundation (CIFF), the Bill & Melinda Gates Foundation (BMGF), and ELMA Philanthropies have pledged funding to support some of the programs that were previously funded by ASCEND, including some deworming programs and some programs treating other NTDs." GiveWell, "Sightsavers — Support for Deworming in Kaduna, Zamfara, Niger, Kano, Adamawa, and Katsina in 2021-2023 (October 2021)".

  • 18 Bill and Melinda Gates Foundation, conversation and email communication with GiveWell, January 25, 2023 (unpublished)
  • 19 Bill and Melinda Gates Foundation, conversation and email communication with GiveWell, January 25, 2023 (unpublished)
  • 20

    See here for Deworm the World's planned allocation of non-Givewell directed funds.

  • 21

    See "Funding landscape" section above.

  • 22

    Deworm the World, conversation with GiveWell, October 24, 2022 (unpublished).

  • 23

    Deworm the World, conversation with GiveWell, October 24, 2022 (unpublished).

  • 24

    WHO, "WHO guideline on control and elimination of human schistosomiasis," February 2022

  • 25

  • 26

    Punjab, Sindh, Khyber Pakhtunkhwa, Balochistan, Islamabad Capital Territory, Azad Jammu and Kashmir, and Gilgit-Baltistan.