As sustainability reporting becomes a global norm, the need for credible and consistent assurance is more critical than ever. International Standard on Sustainability Assurance 5000 General Requirements for Sustainability Assurance Engagements (ISSA 5000) sets a global baseline for sustainability assurance engagements and understanding how to apply its materiality requirements is essential for practitioners.

The case study follows a fictional engagement with ABC plc and is structured around the application of materiality to Scope 1, 2 and 3 greenhouse gas (GHG) emissions disclosures. For the purposes of the case study, it is assumed that the sustainability assurance practitioner is engaged to provide limited assurance services.

The case study:

• Outlines the applicable ISSA 5000 requirements and the various professional judgement points involved in considering or determining materiality for qualitative and quantitative disclosures respectively.
• Demonstrates the assurance practitioner’s considerations when setting thresholds, benchmarks and performance materiality.
• Explores an approach to grouping disclosures logically based on similarity in expression, user interest and user tolerance for misstatement.
• Supports assurance practitioners in assessing the needs and expectations of intended users.
• Guides the addressing of aggregation risk in assurance engagements.
• Navigates application of double materiality in accordance with European Sustainability Reporting Standards (ESRSs).

Supporting information for the case study provides further guidance and context to assist assurance practitioners in implementing ISSA 5000 effectively and consistently.