Double materiality is the analytical foundation of the CSRD reporting framework. Under ESRS 1 (the general requirements standard), companies are required to assess sustainability matters across two distinct dimensions: impact materiality, which asks whether the company's activities cause, contribute to, or are connected to actual or potential impacts on people or the environment; and financial materiality, which asks whether sustainability matters affect or are expected to affect the company's financial position, performance, or cash flows. A matter is included in the sustainability statement if it is material on either or both dimensions — not only when it crosses both thresholds simultaneously.
The double materiality concept predates CSRD — the GRI Standards have used impact-based materiality for years, and the TCFD framework operationalized financial materiality for climate risks. What CSRD adds is the formal requirement to conduct both assessments in a documented, auditable process, and to apply the results to determine the scope of disclosures under each topical ESRS (including ESRS E1 for climate). This walkthrough describes how to structure that assessment so the output will withstand external assurance review.
Step 1: Establish Scope and Governance
Before any analysis begins, the company needs to define the boundaries of the assessment and assign governance accountability. The assessment scope typically covers the company's direct operations and, where relevant, the value chain — both upstream supply chain and downstream use and end-of-life of products. ESRS 1 requires companies to consider the full value chain, but permits proportionality in the depth of the analysis based on available information.
Governance accountability means identifying who owns the assessment process — typically a sustainability, finance, or risk function — and which senior leadership body approves the materiality conclusions. The governance structure must be documented because ESRS 2 (cross-cutting standard) requires disclosure of how sustainability matters are integrated into the company's governance processes, including the role of the management body in oversight.
Step 2: Identify Sustainability Matters to Assess
The starting universe of sustainability matters to assess is defined by the topical ESRS standards. ESRS E1 through E5 cover environmental topics (climate, pollution, water, biodiversity, resource use). ESRS S1 through S4 cover social topics. ESRS G1 covers governance. The double materiality assessment determines which of these topics — and which sub-topics within them — are material for the specific company.
A useful starting point for populating the impact and risk long list is a sector-based analysis. For an industrial manufacturer, the most likely material E1 topics are GHG emissions (almost certain), climate transition risk (probable), and physical climate risk (location-dependent). For a financial institution, Category 15 financed emissions may be more material than own-operations Scope 1 and 2. The sector context shapes which matters are likely to clear the materiality threshold before any quantitative scoring is applied.
Step 3: Score Impact Materiality
Impact materiality assessment evaluates the severity of actual or potential negative impacts (and, under ESRS, the significance of positive impacts) using three criteria from ESRS 1: scale (how widespread is the impact), scope (how severe is the impact), and irremediability (how difficult is it to reverse). For potential impacts — risks of negative impacts that have not yet materialized — likelihood is added as a fourth dimension.
In practice, this scoring is done using a defined scale (commonly 1–5 or 1–3) and a defined threshold above which a matter is considered material. The threshold choice is a judgment call that must be documented and defensible. A matter scored 3/5 on scale, 4/5 on scope, and 3/5 on irremediability might produce an aggregated score that clears the impact materiality threshold — the scoring approach should be consistent across all assessed matters.
Stakeholder engagement feeds impact materiality scoring. ESRS 1 requires companies to engage with affected stakeholders when assessing impacts — this means customers, suppliers, employees, local communities, and civil society organizations relevant to the company's activities. The engagement does not need to be exhaustive, but it must be documented. Common approaches include supplier surveys, employee focus groups, community consultation records, and review of public disclosures or investor questionnaires from customers who are themselves subject to CSRD.
Step 4: Score Financial Materiality
Financial materiality assessment evaluates whether sustainability risks and opportunities are reasonably expected to affect the company's financial position, financial performance, cash flows, or access to finance and cost of capital. This dimension maps closely to the TCFD framework: physical climate risks (acute events like flooding, chronic shifts in temperature), transition risks (carbon pricing, technology shifts, regulatory changes, changing customer preferences), and sustainability-related opportunities.
The financial materiality scoring should reference recognized scenarios. For climate change, ESRS E1-9 requires disclosure of anticipated financial effects under physical and transition risk scenarios — which means the scenario analysis developed for E1-9 disclosure purposes also informs the financial materiality determination for ESRS E1. A company that determines Scope 3 Category 1 emissions are financially material (because a carbon price on upstream supply chain goods would significantly increase input costs) is obligated to disclose the analysis behind that determination.
Step 5: Apply the "Either/Or" Threshold and Document Conclusions
A sustainability matter that clears the impact materiality threshold must be reported on, regardless of whether it also clears the financial materiality threshold. The converse is also true: a matter that clears the financial threshold is required regardless of impact. This "either/or" logic means that topics like biodiversity — which for many companies may not have immediate financial materiality but clearly have impact materiality — are pulled into scope even if the company's CFO views them as non-financial.
The output of the assessment is a materiality matrix (or equivalent structured documentation) showing, for each assessed topic, whether it is material on the impact dimension, the financial dimension, or both. This matrix is disclosed in the sustainability statement under ESRS 2 IRO-1, and the process for conducting the assessment must be described with enough specificity that an external assurance provider can evaluate whether the methodology was sound.
Step 6: Map Materiality Conclusions to Disclosure Requirements
Once the materiality matrix is established, it dictates which topical ESRS disclosure requirements apply. If ESRS E1 climate is determined material, all mandatory disclosure requirements within E1 (E1-1 through E1-9, minus any explicitly voluntary sub-requirements) must be included in the sustainability statement. If ESRS E4 biodiversity is determined not material, those disclosures are omitted, with a brief explanation in the statement.
We're not saying the double materiality assessment is a one-time exercise — ESRS 1 requires companies to update the assessment as business circumstances, value chain relationships, and external context change. A materiality conclusion that was reasonable in 2025 may need revisiting in 2027 if the company acquires a manufacturing business with significant Scope 1 emissions, or if new regulatory requirements (such as EUDR for deforestation) create material financial risks that were not present in the original assessment year.
Common Audit Findings to Pre-empt
Assurance providers conducting limited assurance under ISAE 3000 on CSRD sustainability statements consistently identify the same categories of double materiality assessment deficiencies: insufficient stakeholder engagement documentation; scoring thresholds that are set subjectively and inconsistently applied across topics; financial materiality analysis that uses qualitative language without any quantitative anchoring; and materiality matrix conclusions that exclude topics which competitors with similar business models have determined to be material without a clear differentiated rationale.
For the first reporting year, the goal is not a perfect assessment — it is a documented assessment with a clear methodology, a defensible threshold definition, evidence of stakeholder input, and a transparent record of conclusions. Building that documentation as the assessment is conducted, rather than reconstructing it after the fact, is where most first-year reporting teams save the most time when assurance fieldwork begins.