Audit is a systematic, independent and documented process for obtaining audit evidence and evaluating it objectively to determine the extent to which the audit criteria are fulfilled.
1. Internal audits, sometimes called first-party audits, are conducted by, or on behalf of, the organization and may form the basis for an organization’s self-declaration of conformity. In many cases, particularly in smaller organizations, independence can be demonstrated by the freedom from responsibility for the activity being audited.
2. External audits include those generally termed second- and third-party audits. Second-party audits are conducted by parties having an interest in the organization, such as customers, or by other persons on their behalf. Third-party audits are conducted by external, independent auditing organizations.
3. When two or more auditing organizations cooperate to audit a single auditee, this is termed a joint audit.