Geospatial Impact Evaluations

Program Overview

Rigorous impact evaluations in a fraction of the time of an RCT

Geospatial Impact Evaluations (GIEs) rigorously evaluate the impacts and cost-effectiveness of specific development interventions and large investment portfolios with spatial data. GIEs methods leverage readily available data, like satellite observations or household surveys, to establish a reliable counterfactual for measuring impacts — at a fraction of the time and cost of a “traditional” randomized controlled trial (RCT).

Like RCTs, GIEs can estimate the net, attributal effect of a specific development program by comparing similar groups whose only difference was exposure to the program (or treatment). Unlike RCTs, GIEs use precise geographic data to establish this counterfactual retroactively, eliminating the need to assign program participants into randomized treatment and control groups.

Case Studies

Roads and Transportation

AidData and USAID/West Bank and Gaza have collaborated to conduct an evaluation of the Infrastructure Needs Program (INP) II, which funded the construction of water infrastructure, road networks, and schools with the ultimate goal of improving the Palestinian economy.

Natural Resource Concessions

AidData constructed a new dataset that measures the precise locations of 557 natural resource concessions granted to investors in Liberia, and then then merged these data with a remotely sensed measure of nighttime light growth at the 1km x 1km grid cell level to analyze effects across sectors and investor types.

Indigenous Land Rights

AidData studied whether formalization of indigenous communities' land rights affects the rate of deforestation in both the short and medium terms as the result of KfW-funded land tenure interventions across the Brazilian Amazon from 1997 to 2008.

Chinese Development and Sensitive Forests

What are the conservation impacts of Chinese development activities in ecological hotspots? We generate and sub-nationally geo-reference a dataset of official Chinese development activities implemented between 2000 and 2014 in the Tropical Andes, the Great Lakes region of Africa, and the Mekong Delta. We then merge these project data with a long series of high-resolution satellite data in order to evaluate their impacts on forest cover.

More Case Studies >

Benefits of GIE Methodology

GIEs can be implemented remotely and retrospectively, leveraging existing location-referenced data and generate portfolio-wide insights.


Measure real impact

Geospatial Impact Evaluations measure intended and unintended impacts of development programs. Leveraging readily available data like satellite observations or household surveys, GIE methods establish a reliable counterfactual to measure impact - at a fraction of the time and cost of a "traditional" randomized control trial (RCT).

Methodological rigor

Like RCTs, GIEs can estimate the net effect of a specific program by comparing similar units where the only difference was an intervention, or treatment. Unlike RCTs, GIEs use precise geographic data to establish this counterfactual retroactively, eliminating the need to assign program participants into randomized treatment and control groups within the program design.

Learn more efficiently

GIEs can be completed in a fraction of the time and financial cost of an RCT by eliminating the need for customized data collection in treatment and control groups before, during and after the program.

See portfolio-wide insights

GIE methods are also flexible tools that can either be used to evaluate individual projects or project portfolios.  Whereas RCTs are often implemented in narrowly bounded settings, GIEs can be used with data for an entire country (or even multiple countries), which makes it possible to draw conclusions about impacts and cost effectiveness that are broadly generalizable.

Ascertain long-term impact, even in inaccessible places

Additionally, GIEs can be implemented remotely, retrospectively, and affordably, opening up new opportunities to measure long-run programmatic impacts, which is especially useful to evaluators working in conflict and fragile state settings.

Learn more in our #CGDTalks Video

GIE Methodology

Geospatial impact evaluations (GIEs) rely on subnationally geo-referenced intervention, outcome, and covariate data and quasi-experimental methods of causal inference to measure the intended (or unintended) impacts of development programs.

GIEs seek to mimic the conditions of a randomized control trial (RCT) with observational data. RCTs are powerful because they create conditions under which one can reliably ascertain that individuals’ participation in a program was not correlated with their outcomes. GIEs create similar conditions, but without randomly assigning individuals to treatment and control groups.  

For our in-depth exploration of GIEs, please see A Primer on Geospatial Impact Evaluations Methods, Tools, and Impact Evaluations.

Using counterfactuals to find impact

The key is making comparisons across individuals who are sufficiently similar to one another and experiencing changes that are otherwise similar.  The best way to make such comparisons is to identify comparison individuals who are geographically close to the program participants, but unlikely to be affected by the program’s presence.  Doing so requires geographically precise data on programmatic interventions and their intended (or unintended) outcomes. Such data are rapidly expanding in number, scope, periodicity, and availability.

Rather than using randomization to identify counterfactual cases, GIEs seek to achieve a similar result through one of three methods:

  1. Strategic subsampling of observational data to identify treatment and control cases that are nearly identical but for the presence or absence of the intervention (e.g. propensity score matching)
  2. Comparing the pre- and post-intervention change in the outcome of interest for a treatment group relative to a control group (e.g. difference-in-differences, fixed effects)
  3. Exploiting the discontinuity around a geographic cutoff that is “as-if random” (where the treated cases and control cases on either side of the cutoff are extremely similar across pretreatment covariates)

Featured Publications

Impact Evaluation

Long-term Impact Evaluation of the Malawi Wellness and Agriculture for Life Advancement Program

Ariel BenYishay, Kristen Velyvis, Katherine Nolan, Lila Kumar Khatiwada, Carrie Dolan, Danice Brown Guzman, Tom Purekal, Arif Mamun, Sara Wilf


Impact Evaluation

Building on a Foundation Stone: The Long-Term Impacts of a Local Infrastructure and Governance Program in Cambodia

Ariel BenYishay, Brad Parks, Rachel Trichler, Christian Baehr, Daniel Aboagye, Punwath Prum


Journal Article

The impact of an insecticide treated bednet campaign on all-cause child mortality: A geospatial impact evaluation from the Democratic Republic of Congo


Carrie Dolan, Ariel BenYishay, Karen Grépin, Jeffery Tanner, April Kimmel, David Wheeler, Gordon McCord


Impact Evaluation

Parceling out prosperity? An impact evaluation of natural resource sector investments in Liberia

Brad Parks, Jonas Bunte, Harsh Desai, Kanio Gbala, and Daniel Miller Runfola


Impact Evaluation

Final Report: Evaluation of the On-Farm Water Management Program

Ariel BenYishay, Carey Glenn, Seth Goodman, Dan Runfola, Rachel Trichler


Impact Evaluation

Evaluation of the Local Governance and Infrastructure Program

Pablo Beramendi, Soomin Oh, Erik Wibbels


Program Team

For technical or research inquires, contact:

Research & Evaluation

Ariel BenYishay

Chief Economist, Director of Research and Evaluation

Research & Evaluation

Dan Runfola

Senior Geospatial Scientist

Research & Evaluation

Kunwar Singh

Geospatial Scientist

Research & Evaluation

Christian Baehr

Junior Data Analyst

Research & Evaluation

Katherine Nolan

Senior Research Analyst

Research & Evaluation

Miranda Lv

GIS Analyst


Alex Wooley

Director of Partnerships and Communications