Section 3.55 of the July 2007 Revision of Generally Accepted Government Auditing Standards (GAGAS) requires that:

"Audit organizations performing audits and attestation engagements in accordance with GAGAS must have an external peer review performed by reviewers independent of the audit organization being reviewed at least once every 3 years."
 
The City of Garland's Internal Audit Department has earned a Full Compliance Opinion for its 2009 Peer Review.
 
2009 Peer Review