Maximizing Impact Return on Investment

In my previous post, I explored how my experiences in Scandinavia sparked my interest in sustainable investing. As I continue this journey, I'm increasingly faced with more complex questions: Which investments truly create the greatest impact? How do we measure impact effectively? And how do we navigate the thorny ethical dilemmas that arise when comparing different types of impact?

The Quest for Maximum Impact: Where Should Impact Dollars Flow?

If financial returns were set aside and pure impact was the sole consideration, where would our investment dollars create the greatest good? This question sits at the heart of impact investing yet remains surprisingly difficult to answer definitively. The global impact investing market which is growing rapidly at nearly 19% annually and projected to reach over $7.5 trillion by 2033, demonstrates increasing investor appetite for combining purpose with profit. But not all impact investments are created equal. When examining which sectors receive the most impact capital, patterns emerge. Berkeley-Haas research shows impact funds are heavily concentrated in poverty alleviation (43%), small medium enterprise (SME) funding (42%), and geography specific investments (33%), with environmental impact following at 28%. These allocations differ significantly from traditional venture capital, with impact investing showing stronger representation in food/agriculture, infrastructure, and healthcare compared to the tech heavy portfolios of conventional VC funds. But frequency doesn't necessarily indicate effectiveness. Organizations like the World Bank increasingly highlight the critical intersection of climate and health investments, noting their potential to prevent  ⅓ of climate driven poverty by 2030. Climate change is expected to push 132 million people into extreme poverty by 2030, with health impacts alone driving one third of this increase. Despite this outsized impact, current investments at this nexus remain surprisingly low. Healthcare focused impact investments, like the Stichting Medical Credit Fund in Africa, demonstrate the powerful multiplier effect possible in this sector. By providing nearly 10,000 loans worth over €180 million to more than 2,000 healthcare providers, they've enabled supported facilities to serve 5 million patients annually 55% from low-income communities. The ripple effects extend beyond health outcomes to include financial inclusion, gender equality, and economic development.

The Multiplier Effect

The multiplier effect is a key concept in impact investing, referring to the cascading benefits that arise from an initial investment, where the positive impact extends far beyond the direct beneficiaries. Certain types of investments are particularly effective at generating high multiplier effects because they address systemic issues and create domino effects across communities, economies, and ecosystems. For example, healthcare investments often yield significant multipliers by improving health outcomes, which in turn enhance productivity, reduce healthcare costs, and foster economic growth. As mentioned above a notable case is the Stichting Medical Credit Fund in Africa, which has empowered healthcare facilities to serve millions of patients annually while simultaneously advancing financial inclusion and gender equality. Similarly, education focused investments have a profound multiplier effect by equipping individuals with knowledge and skills that drive economic development, reduce poverty, and improve societal wellbeing.

Clean energy projects also demonstrate high multipliers by reducing carbon emissions while providing affordable energy access to underserved communities. Investments in renewable energy infrastructure like solar  and wind farms can spur local business growth and improve quality of life for entire regions. Agricultural development initiatives are another example. By supporting smallholder farmers with sustainable practices and resources, these investments improve food security, increase incomes, and protect ecosystems. Microfinance programs, which provide small loans to underserved entrepreneurs (often women), empower individuals to start businesses and improve household incomes, creating economic growth that reverberates through their communities.

Among all impact investments, vaccination programs arguably have the greatest multiplier effect of all. Vaccines have eradicated diseases like smallpox and significantly reduced mortality rates from illnesses such as polio and measles. The ripple effects of vaccination programs include improved public health outcomes, increased life expectancy, and substantial economic benefits due to healthier populations contributing more effectively to society. Studies suggest that every dollar spent on vaccines generates $44 in economic benefits through reduced healthcare costs and enhanced productivity.  Here is a {rough} list of the top 10 investments that I could find ranked by economic return per dollar spent. These returns account for direct economic gains, productivity improvements, healthcare cost reductions, and long term human capital development:

1. Deworming Programs for Pregnant Women (Ethiopia)

Return: $648.41 per $1 invested

Targeted deworming interventions for pregnant women in low income regions prevent maternal anaemia, reduce preterm births, and improve childhood development outcomes. This creates intergenerational economic benefits through improved workforce productivity.

2. Large-Scale Deworming Initiatives (Ethiopia)

Return: $378.19 per $1 invested

Mass deworming campaigns in endemic areas reduce school absenteeism by 25% and increase future earnings by 20% for treated children. The economic ripple effects include higher agricultural productivity and reduced healthcare burdens.

3. Engineered Wetland Infrastructure (Global)

Return: $282 per $1 invested

Dow Chemical’s $1 million wetland project replaced a $40 million wastewater plant, generating $282 million in net savings over 20 years. Natural infrastructure solutions often outperform traditional "gray" infrastructure in cost-effectiveness and environmental benefits.

4. Global Infectious Disease Eradication (HIV/TB/Malaria)

Return: $507 per $1 invested

A $97.9 billion global investment in vaccines, diagnostics, and treatments for these diseases is projected to yield $49.7 trillion in economic benefits by 2040 through averted mortality, reduced caregiving burdens, and increased productivity.

5. Measles Vaccination Campaigns (Global)

Return: $44 per $1 invested

The measles vaccine alone accounts for 60% of lives saved by immunization programs. Beyond mortality reduction, it prevents disability-adjusted life years (DALYs) and generates long-term economic gains through healthier populations.

6. Insecticide-Treated Bed Nets (Sub-Saharan Africa)

Return: $23–$35 per $1 invested

Each net costs $2–$4 but averts $90–$140 in healthcare costs and lost productivity per household. Large-scale distributions reduce malaria incidence by 40–55%, freeing up household income for education and entrepreneurship.

7. Rotavirus Vaccination (Low-Income Countries)

Return: $26–$52 per $1 invested

Introducing rotavirus vaccines in eight African nations showed benefit-cost ratios as high as 35:1. Reduced diarrheal disease burdens lower hospitalizations and improve child nutrition, enhancing cognitive development.

8. Early Childhood Health Interventions

Return: $8–$44 per $1 invested**

Nutrition programs and neonatal care yield eightfold returns by improving educational attainment and adult earning potential. For example, iodizing salt prevents cognitive impairments linked to $1 billion in annual lost productivity.

9. Pell Grant Education Funding (U.S.)

Return: $2.80 GDP growth per $1 invested

Each 1% increase in Pell Grants raises local incomes by 2.8% within two years. Grants enable student loan uptake, driving regional economic activity through skilled labor force development.

10. Sustainable Agriculture Training (Global)

Return: $10–$16 per $1 invested

Programs teaching smallholder farmers climate-resilient practices increase crop yields by 30–50%. This stabilizes food prices, reduces poverty-driven migration, and curbs deforestation

Despite their transformative potential, investments with high multiplier effects face challenges such as difficulty in measuring indirect benefits, funding gaps due to lower immediate financial returns compared to other sectors, and ethical dilemmas in prioritizing one type of impact over another. Frameworks like IRIS+ attempt to standardize impact measurement by focusing on dimensions like scale, duration, contribution, and risk. However, these frameworks are not without criticism. They have a tendency to oversimplify complex impacts into quantitative metrics or neglect qualitative aspects of impact that are harder to measure but equally important. Ultimately, investments with high multiplier effects whether in healthcare infrastructure, education programs, renewable energy projects, agricultural development initiatives, microfinance programs, or vaccination campaigns represent some of the most impactful ways to deploy capital. By prioritizing these types of investments, impact investors can maximize their contributions toward systemic change while addressing critical global challenges.

However, determining "greatest impact" depends entirely on how we define and measure impact in the first place, which leads us to the frameworks that attempt to systematize this evaluation.

Effective Altruism: A Framework for Maximizing Impact

Effective altruism offers perhaps the most rigorous framework for quantifying maximal impact. Unlike traditional philanthropy or impact investing, Effective altruism doesn't simply ask "is this good?" but rather "is this the most good possible with these resources?" The Effective altruism framework applies evidence and reason to identify the best ways of helping others, using key principles like prioritization, impartial altruism, and open truth seeking. These principles push investors beyond personal preferences or emotional connections to causes. For effective altruists, the selection of where to invest is driven by frameworks assessing causes based on:

1. Importance - The scale of benefits, effects on other causes, and contribution to societal robustness 
2. Tractability- Existence of defined interventions, academic evidence, expert theory, & track record
3. Neglectedness - Whether society undervalues the cause and opportunities for progress exist

When these frameworks are applied to impact investing, they often lead to different conclusions than mainstream sustainable investing approaches. While traditional ESG investing might focus on large public companies with incrementally better practices, effective altruism influenced investing typically prioritizes interventions with the largest benefit to cost ratios, often in developing regions where the same dollar goes much further.

As David Callahan of Inside Philanthropy notes, "The allure of effective altruism has been that it's an off the shelf methodology for being a highly sophisticated, impact-focused, data driven funder". This approach has led many EA aligned investors toward global health interventions in developing countries, which often show the highest measurable impact per dollar invested. However, the EA approach raises profound questions about how we value different types of impact and the ethical frameworks underlying these valuations.

The Challenging Ethics: Comparing Human and Animal Lives

One of the most difficult ethical questions in impact investing is how to compare vastly different types of impact, particularly when comparing human benefit against animal welfare or environmental protection. Is saving one human life equivalent to saving 1,000 animal lives? 10,000? Is preserving an entire ecosystem worth more or less than building a hospital? Philosopher Peter Singer, whose work heavily influences effective altruism thinking, identifies speciesism as "the view that a being's moral status depends upon its species". Singer argues that species membership alone is morally irrelevant. What matters is a being's capacity to experience suffering or satisfaction.

The utilitarian perspective suggests that "all animals who are capable of pleasure and pain (or satisfaction and frustration) should count equally in our calculations". However, this doesn't necessarily mean human and animal lives should be valued identically. Singer explains: "This does not mean that to avoid speciesism we must hold that it is as wrong to kill a dog as it is to kill a human being in full possession of their faculties...We could still hold, for instance, that it is worse to kill an adult human with a capacity for self-awareness and the ability to plan for the future and have meaningful relations with others, than it is to kill a mouse, who presumably does not share all of these characteristics". When applying these considerations to impact investing, we enter complex territory. Some impact funds explicitly target animal welfare improvements, such as investments in plant based proteins or more humane agricultural systems. Others focus exclusively on human welfare. The challenge comes in comparing these different impacts.

There's no consensus formula stating that X animal lives equal one human life. Different ethical frameworks produce wildly different conclusions. Utilitarians might attempt to quantify relative capacity for suffering, while Kantians might emphasize the unique and irreplaceable value of each being's life.

For impact investors, these philosophical questions have practical implications. When deciding between funding healthcare interventions versus wildlife conservation, how do we weigh these different dimensions of impact? The IRIS+ framework attempts to provide a structured approach to this challenge. 

The IRIS+ Framework: How GIIN Measures Impact

The Impact Reporting and Investment Standards (IRIS+) system, managed by the Global Impact Investing Network (GIIN), represents the most comprehensive attempt to standardize impact measurement across the industry. According to GIIN research, 78% of impact investors use IRIS+ for impact management and measurement. IRIS+ provides a common language for describing, measuring, and comparing impact across five key dimensions:

1. WHAT: Understanding the outcomes the enterprise contributes to and their importance to stakeholders
2. WHO: Identifying which stakeholders experience the effects and how underserved they were
3. HOW MUCH: Quantifying how many stakeholders experienced the outcome, the degree of change, and duration
4. CONTRIBUTION: Assessing whether efforts resulted in outcomes better than what would have occurred otherwise
5. RISK: Evaluating the likelihood that impact will differ from expectations

The GIIN's approach to impact measurement is guided by principles of rigor, independence, replicability, transparency, and mindfulness of incentives. Their methodology involves four sequential steps: binding the sample (determining parameters), collecting standardized information, conducting analysis, and deriving insight. At its core, IRIS+ attempts to make the inherently subjective process of impact assessment more objective and comparable across different investments and portfolios.

Calculating Impact Scores: Methods and Challenges

While IRIS+ provides a framework, the actual calculation of impact scores varies widely across the industry. Several approaches have emerged: The Social Return on Investment (SROI) methodology uses a relatively straightforward formula: SROI = (Social and Environmental Value Created / Financial Cost of Investment) × 100% For example, if an investment produces $100,000 worth of social and environmental value at a cost of $50,000, the SROI would be 200%, meaning every dollar invested generates $2 in social and environmental return. Other approaches take different angles. The Inspire Impact Score analyzes both negative and positive impacts, using 26 materiality categories defined by the Sustainability Accounting Standards Board (SASB), but applying them through a specific worldview. This approach ranks companies against industry peers on a scale of 0-100 for each category. Global Endowment Management uses a two dimensional approach combining Portfolio Scores (measuring impact on stakeholders) and Manager Scores (measuring manager actions) visualized on an Impact Map. These varied approaches highlight a fundamental challenge: impact measurement inevitably involves value judgments about what counts as "impact" and how different types of impact should be weighted.

Criticisms and Alternatives: Beyond IRIS+

Despite its widespread adoption, IRIS+ and similar frameworks face significant criticisms. Among the most common:

1. Fragmentation across frameworks: Despite progress in standardization, the proliferation of different impact measurement frameworks creates confusion.
2. Reductionist approach: IRIS+ has been criticized for being "single-figure heavy" compared to GRI's more narrative approach, potentially oversimplifying complex impacts.
3. Data quality and availability issues: Not all impact areas have equally available or reliable data, creating biases in measurement.
4. Potential for impact washing: As with ESG more broadly, standardized metrics can be manipulated or selectively reported to present an overly positive picture.

Emerging alternatives seek to address these limitations. Impact valuation approaches like the Value Balancing Alliance (VBA) methodology translate sustainability impacts into monetary terms for more objective assessment. The ROSI™ (Return on Sustainable Investment) and Impact Weighted Accounting (IWA) frameworks offer complementary approaches that monetize internal and external impacts.

My Evolving Perspective

As my understanding of impact investing deepens, I find myself both impressed by the rigor of frameworks like IRIS+ and a=effective altruism, yet also aware of their limitations. The attempt to quantify something as complex and subjective as "impact" inevitably simplifies and potentially distorts the very thing we're trying to measure.

If I were seeking to maximize the impact of my investment dollars today, I'd likely focus on the intersection of climate and health in developing regions where I would be able to get the highest multiplier effect on the capital I deployed and also reap a small financial return on investment which is crucial to convincing investors to come aboard.  At the same time, I recognize my conclusion itself reflects value judgments about what constitutes "greatest impact."

My greatest question remains: Can we truly measure impact in a way that captures its full complexity? Or are we simply creating metrics that make us feel better about our investment decisions?  What do you think is the most impactful investment? 

Final Thoughts

One last thing that I would like to note is that I have also thought about the fact that humans are also the most destructive and heedless of all of earth's creatures. With that in mind, I have also thought about the possibility that there could be a framework that exists that actually weighs investments geared toward the downfall or destruction of humanity as having the greatest impact. As I pondered this idea, I also realized that although that may be true and some may view humanity as a virus of sorts, we also are the only beings that have an ability to curtail our behaviour and measure and make the necessary changes in our behaviour to fix the destruction we are causing. Viruses, as parasitic entities, do not inherently aim to kill their hosts. Their primary objective is survival and replication, which often requires utilizing the host's resources to reproduce. In most cases, viruses benefit from keeping their host alive and functional, as this ensures continued replication and transmission to new hosts. From an evolutionary perspective, a virus that kills its host too quickly may limit its own ability to spread, which is why many viruses evolve toward a balance between virulence and transmissibility. 

We are the only species in the universe that we know about who has the ability to survive and endure anything that is thrown at us. Let’s start deploying more money towards net positive projects that aim to prolong earth’s natural resources. Let’s not kill our host because if we do, we are going to kill our species right along with it.