Which organizations should undergo external QAS?

All internal audit functions, regardless of size or whether they are outsourced or co-sourced, should undergo external quality assessments. Ongoing and periodic internal assessments lay the foundation for external assessments, and together, internal and external assessments make up the Quality Assurance and Improvement Program (QAIP).  An IA function cannot be in conformance with the Standards without conducting a quality assessment at least once every five years.