Impact Measurement
The problem with how the world
measures impact
For decades, organisations trying to prove their social and environmental impact have relied on frameworks that were never built for the job.
SROI was a great first step. It delivered a method to measure the value of social investment.
Social Return on Investment promised a single ratio that could express human benefit in financial terms. In practice it produced numbers that were unverifiable, incomparable across sectors, and routinely gamed. A £1 invested returning £8 of social value told you nothing about what actually changed for whom, or for how long.
Carbon markets exposed the same failure.
Projects generating carbon credits claimed impact across millions of lives, but the causal chain between a carbon offset and a verifiable human outcome was rarely interrogated. When it was, the gap between claimed and actual impact was frequently significant. The methodology was the problem, not the intent.
Organisations reported outputs, numbers reached, tonnes diverted, kilowatts generated, and called them outcomes. The market for impact evidence was, in effect, broken.
A new framework was needed.
Not another ratio. Not another scoring system. A methodology that could answer a single, auditable question: how many lives were meaningfully changed, and how do you know?
Symolem proposed a solution for this gap.
The Human Impact Equivalence Framework®, tested across voluntary carbon markets, green hydrogen, plastic credit schemes and fashion supply chains. It was applied at scale to assess the impact claims of nearly 10,000 entrants to the Zayed Sustainability Prize, and is currently being tested at the University of Exeter. The methodology was built to hold up under that scrutiny. It does.
10,000
impact claims assessed
Zayed Sustainability Prize
impact framework authored
University of Exeter
currently under academic test
Impact Reports
Measurement without a report is data.
A report without measurement is a story.
Symolem produces institutional-grade impact reports for companies, NGOs, and development organisations that need to evidence their social and environmental outcomes to the audiences that matter most, investors, funders, regulators, retail buyers, and the public.
Every report is built on the HIE® Framework. That means the impact claims inside it are not self-declared, they are derived from a structured methodology, tested against the Causal Integrity Test, and expressed in a single comparable unit: impacted lives. The result is a document that can withstand scrutiny, not just satisfy a reporting obligation.
This matters because the audiences for impact evidence have changed. Investors are applying increasing rigour to ESG claims following a decade of greenwashing litigation and regulatory tightening. NGO funders, institutional, philanthropic, and governmental, are demanding outcome evidence, not activity logs. Retail buyers assessing supplier sustainability credentials under ESPR need data they can verify, not narratives they have to trust.
A Symolem impact report gives organisations something most impact reporting cannot: a number that means something. How many lives were reached. How directly. Over what timeframe. And why the methodology that produced that number holds up.
Deliverables
What a Symolem impact
report includes
Baseline assessment
Current impact claims and data infrastructure evaluated.
HIE® methodology applied
Across programmes, products, or supply chain interventions.
Causal chain mapping
Outcomes traced back to the primary intervention.
Three Degree Rule
Claims extend only as far as the evidence supports.
Final impact figure
Expressed in impacted lives, with full audit trail.
Publication-ready report
Formatted for investor, funder, or regulatory audiences.
Clients
Who we work with
Companies requiring investor-grade sustainability evidence beyond ESPR minimum disclosure.
NGOs and development organisations reporting to institutional funders.
Brands building supply chain impact credentials for retail buyer due diligence.
Any organisation that needs to say how many lives their work has changed, and prove it.
HIE® is one of three Symolem frameworks. See also the 6M Model for textile circularity and START for compliance capability.
HIE® in the field
BALWA Africa Enterprise
BALWA Africa Enterprise is a tailoring and vocational training hub based inside Kakuma Refugee Camp in north-western Kenya. It equips refugee and host-community women with the skills, equipment and market access to build livelihoods through garment production, restoring agency where displacement removed it.
Symolem applies the HIE® Framework to BALWA's programmes to quantify outcomes in impacted lives — a defensible figure that funders, retail partners and regulators can rely on, rather than an activity count.
Read the BALWA case study →HIE® in the field
Landfills2Landmarks
Landfills2Landmarks is a UN-accredited NGO working on textile waste, extended producer responsibility and circular infrastructure across Ghana and the United Kingdom, where Lavinia Fernandes serves as Vice-Chair.
The HIE® Framework is applied to the Foundation's programmes to establish what will be evidenced before any outcome is claimed.
Read about Landfills2Landmarks →Proprietary Methodology
THE HIE®
FRAMEWORK
Beyond compliance. Into evidence.
ESPR sets the floor. The Human Impact Equivalence Framework® takes you above it. Where ESPR requires you to disclose sustainability data, HIE® translates that data into a single metric, impacted lives, that investors, retail buyers, and sustainability-conscious consumers can actually act on.
Developed across voluntary carbon markets, green hydrogen, plastic collection, and fashion supply chains, HIE® is the only impact measurement methodology purpose-built for the circular economy context that ESPR creates.
Two-Layer Structure
Direct and systemic impact layers measured separately, maps to ESPR's Scope 1/2/3 disclosure requirements.
Three Degree Rule
Causal Integrity Test ensures your sustainability claims extend only as far as verifiable evidence supports, greenwashing-proof by design.
Primary Intervention Rule
Proportional attribution across multi-tier supply chains, essential for ESPR's multi-actor DPP data requirements.
Temporal Discount Rate
Time-adjusted impact across the product lifecycle, from design and manufacturing through use and end-of-life.
Why HIE® matters for ESPR compliance
ESPR requires disclosure. It does not tell you how to make that disclosure commercially valuable. Brands that only meet the minimum will be commoditised by compliance. Brands that translate their ESPR data into genuine impact evidence will differentiate. HIE® is how you do that.
Methodology
Human Impact Equivalence
Framework®
The HIE® Framework is a proprietary methodology for quantifying social and environmental impact in a single, comparable unit, impacted lives. Developed to cut through the fragmentation of impact metrics across sectors, HIE® enables organisations to make rigorous, auditable claims about the human significance of their work.
Applied across impact sectors
Anywhere a credible, comparable measure of human benefit is required.
COMMON QUESTIONS
HIE®, the Causal Integrity Test and the Three Degree Rule
What is the Human Impact Equivalence Framework (HIE®)?
The Human Impact Equivalence Framework® is Symolem's proprietary methodology for quantifying social and environmental outcomes in a single comparable unit — impacted lives. It lets organisations compare, aggregate and defend outcomes from very different interventions on a like-for-like basis. HIE® has been applied at scale to nearly 10,000 impact claims for the Zayed Sustainability Prize and is currently being tested at the University of Exeter.
How does HIE® differ from carbon accounting or ESG scoring?
Carbon accounting measures emissions; ESG scoring rates disclosure practice. Neither answers the question a regulator, investor or customer actually asks: what human outcome did this intervention produce, and can you prove it? HIE® measures the outcome itself — expressed as impacted lives — and traces it back to the intervention through a Causal Integrity Test. It sits alongside carbon and ESG reporting, not in place of it.
What is the Causal Integrity Test?
The Causal Integrity Test is the mechanism inside HIE® that traces every claimed outcome back to the primary intervention. It asks whether the evidence trail is intact, whether attribution is proportional across the parties involved, and whether the claim survives independent scrutiny. If an outcome cannot be traced with integrity to the intervention, it does not count. That is what makes HIE® greenwashing-proof by design.
What is the Three Degree Rule?
The Three Degree Rule is the attribution boundary inside the Causal Integrity Test. It limits claimed outcomes to those within three causal degrees of the intervention. Beyond three degrees, the evidence chain becomes too diluted to defend and the claim is excluded. The rule stops organisations extending impact claims into territory the underlying evidence cannot support, which is where most greenwashing exposure sits.
Who uses HIE® and for what?
HIE® has been used to assess voluntary carbon market projects, green hydrogen schemes, plastic credit programmes and fashion supply chains. It underpinned the impact assessment methodology for nearly 10,000 entrants to the Zayed Sustainability Prize and is currently under academic test at the University of Exeter. Symolem uses HIE® to produce defensible impact reports for brands, retailers, funders and awarding bodies that need to substantiate outcome claims to regulators, investors or the public.
Further reading
Read more on this
What we do
Where to go next
Plain-English pages on the rules that apply to you, the evidence you need, and the people who do the work.
Looking for something specific? See every page on the site.