Power calculation for causal inference in social science: sample size and minimum detectable effect determination | 3ie

What we offer
At the core of our work, impact evaluations are rigorous studies that measure the effects of international development programmes. We focus on conducting impact evaluations on policy-relevant research questions where credible findings can drive decision-making.

3ie invented evidence gap maps, which provide a visual overview of existing and ongoing studies or reviews in a sector or sub-sector of international development. These maps help policymakers find the most relevant evidence for a given question, thereby improving decision-making.

Our synthesis products, including systematic reviews, integrate findings from multiple different studies which address a common research question. Because they look systematically across the evidence base to see what works and why, systematic reviews and other synthesis products are more reliable for decision-making than results from a single study used in an ad hoc way.

Often, policy decisions must be made quickly. To make sure that decision-makers get the evidence they need when they need it, 3ie has developed a set of helpdesk services and rapid evidence products. Our Rapid Response Briefs and Rapid Evidence Assessments draw from the latest high-quality research to answer policy questions in a fraction of the time of traditional evaluations or systematic reviews.

We work with governments and other organizations to build their capacities in evaluation and evidence-informed decision-making. In addition to providing trainings on a wide range of evaluation methods, we offer ongoing support services to ensure our partners have access to the most up-to-date evidence and evaluation tools.

3ie specialises in increasing access to, demand for and use of evidence by governments, parliaments, programme managers, civil society, programme participants and the media. We do this by emphasising the value of planning and engaging with stakeholders to ensure that evaluations and reviews are relevant and useful. We use robust and effective monitoring to measure evidence use so that we can convey evidence impact on programmes and policies with greater confidence.

Since 3ie was founded, transparent, reproducible and ethical evidence (TREE) have been core considerations in our work. We have developed and refined tools and best practices to ensure our studies apply technically rigorous methodologies, transparently share design and analysis decisions, yield computationally reproducible analysis, and incorporate foundational principles of research ethics into design, implementation, and dissemination. 3ie’s transparent, reproducible and ethical evidence (TREE) Policy articulates this commitment to TRE best practices.
Evidence hub
3ie’s Development Evidence Portal is the largest-of-its-kind repository of rigorous evidence on what works in international development. This portal includes evaluations and synthesis of studies conducted in low-and middle-income countries. It combines records from 3ie’s Impact Evaluation and Systematic Review repositories, as well as, evidence gap maps.

These provide a visual display of completed and ongoing systematic reviews and impact evaluations in a sector or sub-sector, structured around a framework of interventions and outcomes.

Evidence impact summaries briefly describe how 3ie-supported evidence has informed and influenced decision makers. Each summary highlights verified instances of evidence impact.

We provide funding for replications, conduct in-house replication research and publish guidance on replication methodology. We also provide funding to original authors of 3ie-funded for preparing their raw datasets.

As part of our mandate as a knowledge producer and translator for our main audiences, we publish a range of knowledge products. These include briefs, impact evaluation reports, systematic review reports and summaries, replication papers, evidence gap map reports, scoping reports and working papers.

3ie’s Registry for International Development Impact Evaluations (RIDIE) aims to enhance the transparency and quality of impact evaluation research before it begins.
Our work
- Working with governments
3ie’s evidence programmes support studies to fill critical knowledge gaps in a sector, sub-sector or in an area with limited rigorous evidence. We fund studies under a specific theme or which address a particular question or set of questions in programme areas where our donors want to expand global public knowledge of what works and what does not.

Improving adolescent sexual and reproductive health requires decision-makers to have evidence on what works or not, for whom and why, particularly in low- and middle-income countries (L&MIC).

Despite the availability of agricultural technologies, few smallholder farmers in developing economies adopt new inputs and practices. One of the factors preventing this is the lack of effective knowledge dissemination.

Agriculture is a major source of sustenance for rural populations in low- and middle income countries. But owing to weather, pests, diseases and price fluctuations, farmers face numerous risks, including crop and livestock losses.

The production and consumption of fish, a nutritious source of food for around one billion people, is rising globally. The bulk of aquaculture still originates from small-scale farming in developing countries, such as Bangladesh.

According to the United Nations estimates, 103 million youth worldwide lack basic literacy skills, and more than 60 per cent of them are women.

3ie is working with USAID’s Center of Excellence on Democracy, Human Rights, and Governance (DRG Center), and NORC at the University of Chicago to increase knowledge on the global advancement of democracy, human rights and governance.

South Asia, home to 600 million children, has the highest number of young people globally. While these youth contribute to the social and economic stability and prosperity of their families, communities and countries, they face several threats to their health, education and protection, including pressures to drop out of education, become child workers, marry and reproduce early.

3ie projects and programs are uncovering ways to promote gender equality and women’s empowerment. Our cross-cutting work seeks to inform what makes development interventions gender-sensitive and transformative in low- and middle-income countries, including challenging fragile contexts.

3ie, funded by the Bill & Melinda Gates Foundation, is supporting studies and other work on HIV combination prevention to maximize the useful knowledge and policy implications from these interventions.

To gain a better understanding of whether providing HIV self-tests to people would increase HIV testing rates, and who might benefit most from availability of tests, 3ie funded seven pilot interventions and their impact evaluations in Kenya, Uganda and Zambia.

The Saamuhika Shakti or Collective Impact initiative aims to improve the lives of waste pickers in Bengaluru, in India’s southern state of Karnataka, through a coordinated multi-sectoral approach.

We are supporting the generation of rigorous evidence in humanitarian contexts on interventions related to water, sanitation and hygiene, food security, multi-sectoral humanitarian programming and interventions targeting malnutrition.

In alignment with our mission, 3ie promotes rigorous, efficient, and ethical use of innovative data sources for impact evaluations, including in those conducted by 3ie, by 3ie research partners, and in the global development community more broadly.

A major challenge in the fight against vaccine-preventable deaths and diseases is the limited evidence available on innovative and successful community-based approaches for expanding immunization coverage in countries with low or stagnating vaccination rates.

Much of the evidence surrounding the integration of HIV services with maternal, neonatal, and child health services, as well as with sexual and reproductive health and family planning services, does not come from rigorous studies.

Widespread hunger, malnutrition, and water insecurity have devastating and long-lasting impacts on the health and well-being of millions of people around the globe.

With more than three billion people living in contexts that are highly vulnerable to climate change (IPCC Report 2022), mitigation and adaptation strategies are essential to minimize the long-term effects of climate warming. 3ie’s climate change research program focuses on promoting evidence-informed policies and programs to strengthen climate mitigation efforts.

3ie, the World Health Organization and the Partnership for Maternal Newborn & Child Health worked together to create a gap map to assess the evidence available on social, behavioural and community engagement interventions related to reproductive, maternal, newborn and child health programs in low and middle-income countries.

Everyone needs reliable access to a sufficient quantity of affordable, nutritious food. However, all too often, this need is not fulfilled. Despite best efforts, significant gaps persist between global nutrition targets and actual achievements.

Fragility has expensive, long-term consequences and trying to build peace in situations of protracted conflicts is becoming the norm. In 2016, 1.8 billion people – nearly a quarter of the world's population – were living in situations of fragility. Social cohesion is widely considered important in building sustainable peace in fragile contexts.

Safe sanitation is a key determinant of many public health outcomes and ending open defecation is necessary in order to achieve safe sanitation. To this end, the Indian government has led a massive sanitation program, Swachh Bharat Abhiyan - Gramin, to improve latrine access and use.

Launched in 2011, the National Rural Livelihoods Mission (NRLM) aims to link the rural poor in India to sustainable livelihood opportunities and financial services.

We set up our Replication Programme to address the need for a freely available global public good that helps improve the quality and reliability of impact evaluation evidence used for development decision-making. Replication is the most established method of research validation in science, yet it has not been fully embraced by the research community or development donors, leading to this gap.

3ie, in partnership with the Water Supply and Sanitation Collaborative Council (WSSCC), developed this program to build the evidence base in L&MICs and to support global efforts towards increasing equitable access to and use of WASH services.

We support impact evaluations to build the evidence base on the effectiveness of interventions that reduce the risks faced by the poor through participation in public works and employment programmes.

3ie, with support from the Bill and Melinda Gates Foundation, is undertaking a learning study to understand the barriers and facilitators in programs related to fecal sludge and septage management in the states of Odisha, Tamil Nadu and Telangana.

3ie, in partnership with the Millennium Challenge Corporation (MCC), is working to strengthen evidence use in MCC’s program designs and investment decisions. 3ie will support MCC to ensure their economic modelling, project design and evaluation approaches are at the cutting edge of development science while simultaneously building a repository of learning that benefits other policymakers and funders.

India has one of the lowest female labor force participation rates in South Asia. Among rural women, less than 30 per cent are engaged in productive work, paid or unpaid.

The natural resource governance sector is under-researched and programs in it are under-evaluated. 3ie supported seven impact evaluations to fill critical knowledge gaps on what works to improve governance in the extractives sector in low- and middle-income countries.

3ie champions the research transparency and reproducibility movement as a means of understanding and mitigating challenges to the credibility of social science research, while also working toward stronger integration of ethical principles into practice.

It is widely recognized that preventive measures are crucial in tackling the HIV epidemic in Sub-Saharan Africa. Three randomized controlled trials and numerous observational studies have shown that male circumcision reduces HIV acquisition by approximately 60 per cent for men, suggesting that efforts to increase male circumcision can play a significant role in HIV prevention.

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3ie, in partnership with the Philippines National Economic and Development Authority (NEDA) and Australia’s Department of Foreign Affairs and Trade, is implementing a multi-year Philippines Evidence Program (also known as Policy Window Philippines).

Working in collaboration with the Office of the Prime Minister, the primary aim is to improve developmental outcomes through evidence-informed decision making in Uganda. 3ie is currently supporting evaluation of government programmes around youth livelihood, family planning, public service delivery and local governance, and universal primary education.

3ie and the government of Benin are working on a a multi-year regional initiative that aims to promote the institutionalization of evaluation in government systems across eight countries in West Africa, including: Benin, Burkina Faso, Côte d’Ivoire, Guinea-Bissau, Mali, Niger, Senegal and Togo.
Funding
- Open opportunities
View our current funding opportunities for evaluations, systematic reviews and internal replication studies.

This manual, developed in-house by 3ie's Eric Djimeu and Deo-Gracias Houndolo, presents the basic statistical concepts used in power calculations for experimental design. The authors draw from real world examples to calculate statistical power for individual and cluster randomised controlled trials. The manual is accompanied by the Sample size and minimum detectable effect calculator©, a free online tool developed by the authors that allows users to work directly with each of the formulae presented in the manual.

Working Paper 52, 2022

A framework for examining women’s economic empowerment in collective enterprises

Working paper 3ie

2022 Women-owned collective enterprises are seen as vehicles for promoting economic empowerment. To assess how collective enterprise-based interventions can lead to empowerment, it's important to understand the pathways to change. The authors of this paper examine these pathways and provide a framework that can guide decision-makers, practitioners, and researchers on what inputs, outputs and outcomes should be considered for designing, monitoring and evaluating a program similar to 3ie's Swashakt program.

Understanding caste-based differences in self help groups: Evidence from India’s NRLM program

Understanding caste-based differences in self help groups: Evidence from India’s NRLM program

Working paper 3ie

2022 Authors of this paper analyze the caste-based differences in office bearer positions, participation and benefits received by women who are members of self-help groups under India’s National Rural Livelihoods Mission.

Incorporating process evaluation into impact evaluation: what, why and how

Incorporating process evaluation into impact evaluation: what, why and how

Working paper 3ie

2022 The authors of this paper lay down guidelines that can provide impact evaluators with tools and ideas on how to explore and add relevant elements of process evaluations to experimental and quasi-experimental impact evaluation designs.

Promoting women’s groups for facilitating market linkages in Bihar, India

Promoting women’s groups for facilitating market linkages in Bihar, India

Working paper 3ie

2021 Authors of this paper analyze the effects of market linkages on women's agricultural producer groups, which are part of the Women's Advancement in Rural Development and Agriculture (WARDA) project in Purnea District, Bihar.

What stimulates the demand for grid-based electrification in low-and middle-income countries?

What stimulates the demand for grid-based electrification in low-and middle-income countries?

Working paper 3ie

2021 Authors of this paper outline the findings from a rapid evidence assessment that synthesizes available rigorous impact evaluations of interventions that stimulate demand for electrification in resource-constrained settings.