4. Systematic procedures
To enhance consistency and reliability, an environmental audit should be conducted according to documented and well-defined methodologies and systematic procedures. It should be carried out it accordance with any guidelines developed for that particular type of environmental audit. (For example ISO have published guidelines for conducting environmental management system audits - ISO 14011.)
5. Audit criteria, evidence and findings
Audit criteria should be determined at an early stage of the audit process. They should be agreed between the lead auditor and the client and communicated to the auditee. Audit evidence should then be collected and evaluated in order to determine whether the audit criteria have been met.