We perform our audits in accordance with the international auditing standards and code of ethics, which we apply to the specific EU context. These standards help ensure the quality, professionalism and effectiveness of our work. We also contribute to the development of the standards as part of our international cooperation activities.

The statement of assurance audits

The statement of assurance is our annual financial and compliance audit of the reliability of the EU's accounts and the regularity of the underlying transactions. We publish the resulting findings, conclusions and audit opinions in our annual reports. The audit includes testing a statistically representative sample of transactions and evaluating supervisory and control systems to determine whether revenue and payments are calculated correctly and comply with the legal and regulatory framework. Detailed testing covers all spending schemes and member states and is used to provide specific assessments of the different areas of the EU budget. We also use the work of other auditors as evidence to support our conclusions.

Performance audits

In our performance audits, we address the quality of EU revenue or spending, and whether the principles of sound financial management have been applied. These audits involve an examination of programmes, operations, management systems and procedures of bodies and institutions that manage EU funds, to assess whether they are achieving economy, efficiency and effectiveness in the use of those resources. Our performance audits cover a wide range of topics with a particular focus on issues related to growth and jobs, European added value, management of public finances, the environment and climate action. We publish the results of our performance audits in special reports and bring together findings in this area in an annual report on performance.

Auditing performance involves assessing different aspects of the public intervention process, including inputs (financial, human, material, organisational or regulatory means needed for the implementation of the programme), outputs (the deliverables of the programme), results (the immediate effects of the programme on direct addressees or recipients) and impacts (long-term changes in society that are attributable to the EU's action).



The ECA conducts its audits in accordance with ISSAIs, the international standards on auditing issued by INTOSAI(opens in new window). INTOSAI is the international organisation of supreme audit institutions worldwide. We are currently chair of INTOSAI's Professional Standards Committee(opens in new window), which takes a leading role in developing these standards.

AWARE – methodology and guidance


More details of our audit approach can be found in our online methodology and guidance platform AWARE (Accessible Web-based Audit Resource for the ECA). AWARE consolidates all our audit resources in one easy-to-access tool, providing practical support for our auditors in their daily work.

AWARE sets out the principles we follow in our work and provides guidance on how to apply them in practice, in order to achieve the expected quality of output. It provides guidance on our financial, compliance and performance audits as well as our reviews and opinions.

Information on how AWARE is organised(opens in new window) can be found in the platform itself.

Helping to fight fraud against the EU budget


The European Anti-Fraud Office (OLAF) is responsible for the EU's fight against fraud and for protecting its financial interests. In accordance with ECA Decision No 43-2017 (which lays down arrangements for cooperation with OLAF), we forward to OLAF any suspicion of fraud, corruption or other illegal activity affecting the EU's financial interests. We sometimes identify cases of potential fraud through our audit work, or when communicated to us by third parties.


The EPPO is the EU's new independent public prosecution office, responsible for investigating, prosecuting and bringing to judgment crimes affecting the EU's financial interests. The ECA and the EPPO have signed a working arrangement, which came into effect on 3 September 2021. It sets out a structured framework for establishing and maintaining a cooperative relationship between both parties in order to protect the EU budget, while fully respecting the mandates of both institutions.

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