An ESG materiality assessment is the most important piece of sustainability work most organisations do — and the one most often skipped, mis-scoped or quietly outsourced to a consultant who returns a deck nobody reads. Done properly, the assessment tells the organisation which environmental, social and governance issues actually matter — to the business, to its stakeholders, and to the investors, regulators and customers whose decisions affect its future. Done badly, it produces a colourful matrix and changes nothing.
This is a six-step, practical guide to running a materiality assessment that produces decisions. It is written for Nigerian executives, sustainability leads, CFOs and boards that have committed to ESG reporting and want the underlying work to be credible — to themselves, to regulators (NGX listing rules, FRC sustainability assurance expectations, the IFRS S1/S2 standards that international investors are already asking about) and to the people who read sustainability reports for a living.
What "material" means in ESG
Materiality in ESG is a sharper concept than the word's everyday use suggests. Two definitions sit alongside each other.
Financial materiality — the ESG issues that are reasonably likely to affect the organisation's financial performance, position or value. This is the definition the ISSB's IFRS S1 and S2 standards use, and the one investors care about.
Impact materiality — the ESG issues on which the organisation has a significant impact on people or the environment, regardless of whether that impact returns to the income statement. This is the definition the European Sustainability Reporting Standards use, and the one regulators and civil-society stakeholders increasingly care about.
A serious materiality assessment runs both lenses. The combined approach is called double materiality, and it is becoming the default for organisations that report under more than one framework or that operate across jurisdictions.
The six steps
Step 1 — Define the perimeter
State, in writing, what the assessment covers and what it does not. The perimeter has three dimensions.
The entity — which legal entities, business units and geographies are in scope. For a Nigerian group with subsidiaries elsewhere, this is rarely obvious.
The value chain — upstream (suppliers, raw materials, inbound logistics), own operations (sites, employees, products) and downstream (distribution, use, end of life). Most material impacts in Nigerian businesses sit in the value chain, not in own operations.
The time horizon — short term (one to three years), medium term (three to ten) and long term (beyond ten). Climate-related issues in particular are material on long horizons even when they appear immaterial today.
Document the perimeter. The same document is later evidence to the assurance provider.
Step 2 — Build the long list of issues
Draw from four sources, in this order.
Standards and frameworks. GRI Standards, SASB sector standards, IFRS S1 and S2, the Nigerian Sustainability Reporting Framework where applicable. Use them as a checklist of issues to consider, not as a list to copy.
Sector intelligence. What issues do peers in the same sector report on? What issues do their investors, lenders and customers ask about? In Nigeria, sector context matters — the issues that are material for an oil and gas operator differ from those for a bank, a telecoms provider or a manufacturer.
Internal sources. Risk register, internal audit reports, regulator correspondence, customer complaints, employee survey themes, incident logs. Material issues almost always show up in internal data before they show up in sustainability discussion.
Stakeholder signals. What have your investors, regulators, employees, communities, customers and NGOs raised in the past two years? Document the signals; they become the evidence base for stakeholder engagement in step three.
A long list of 40 to 60 issues is normal. Resist editing at this stage.
Step 3 — Engage stakeholders, with structure
Stakeholder engagement is where materiality assessments either earn credibility or lose it. Three rules apply.
Define the stakeholder groups deliberately — investors and lenders, regulators, customers, employees, suppliers, communities affected by operations, and civil-society organisations that follow the sector. Decide, for each, how their views will be gathered: interviews, structured surveys, focus groups or analysis of existing material.
Use the same long list of issues across all groups. Asking different groups about different issues produces a matrix that cannot be compared.
Document who was engaged, when, by whom and on which issues. This is the section the assurance provider tests first.
For Nigerian organisations, community engagement deserves disproportionate attention. Communities near operations are often the most affected and the least heard; a materiality assessment that does not engage them is incomplete.
Step 4 — Score each issue, twice
For each issue on the long list, score it against the two materiality lenses.
Financial materiality — assess likelihood and magnitude of financial effect. Likelihood is informed by the risk register and the time horizon. Magnitude is informed by financial modelling where possible (climate scenario analysis, regulatory cost modelling, supply-chain disruption modelling) and by structured judgement where modelling is not possible.
Impact materiality — assess the severity and likelihood of the impact on people or the environment. Severity has three sub-dimensions: scale, scope and irremediable character.
Use a defined scoring scale (we use 1–5 for each lens) and a defined methodology document. The scores themselves matter less than the discipline of arriving at them consistently across the long list.
Step 5 — Plot, prioritise, decide
A double-materiality matrix plots impact materiality on one axis and financial materiality on the other. Issues in the upper-right quadrant are material on both lenses; these are the priority topics for disclosure, target-setting and management action. Issues material on only one lens are still material — they belong in disclosure under the relevant framework, even if they do not drive the company's own target-setting.
The output of step five is not the matrix. It is a short list — typically 10 to 15 issues — that the organisation commits to disclose, manage and report progress against. Each priority issue has a named executive owner.
Step 6 — Publish, reassess, evolve
Disclose the methodology, the stakeholder engagement summary and the priority issues in the next sustainability report. The methodology section is what assurance providers test.
Reassess at least every two years, and more frequently if the business or its operating context changes materially — a major acquisition, a new regulatory regime, a significant incident, a shift in investor expectations. Materiality is not a one-off exercise; it is a recurring discipline.
What a credible assessment avoids
Outsourcing the entire exercise to a consultant. The methodology is the output; if the organisation cannot defend it internally, it cannot defend it to assurers.
Asking only internal stakeholders. The result is a flattering matrix that misses the external issues the organisation will eventually be measured on.
Scoring issues only on financial materiality. This is the common Nigerian mistake — and the one that creates problems when international investors apply double materiality in their assessment of the organisation.
Letting the long list shrink before stakeholder engagement. Issues removed before stakeholders are asked cannot be restored without compromising credibility.
Producing a matrix that does not change anything. If the materiality assessment is not visibly informing strategy, targets, disclosure and the board agenda, it has not been done — only performed.
Where the board fits
The board — or the committee to which sustainability oversight is delegated — should approve the methodology before the assessment runs, review the priority issues before publication, and revisit them at least annually. Materiality is a governance topic; the board's fingerprints should be on it.
How Outliers can help
The Outliers ESG & Sustainability Centre publishes a working ESG Materiality Assessment Toolkit — the methodology, the long-list templates, the stakeholder engagement guide, the scoring matrix and the disclosure-ready outputs that Nigerian organisations need to run a credible assessment.
If your organisation is preparing for its next sustainability report, or is starting the work for the first time, the ESG & Sustainability Centre is the right place to begin. The full ESG resources library hosts the policies, frameworks and assessment tools the centre maintains, and the Materiality Assessment Template itself is the document to start with — the Double Materiality Matrix sits alongside it for the scoring step.
A credible materiality assessment is the foundation everything else in ESG rests on — targets, disclosure, assurance, strategy. The six steps are not complicated. The discipline to follow them honestly is what separates the organisations that are taken seriously on sustainability from those that are not.