The definition of attestation is to affirm to be correct. In accounting, an attestation engagement is the process of providing an opinion on published financial and other business information of a business, public agency or other organization.
The AICPA’s Auditing Standard Board (ASB), recently issued clarifying Statements on Standards for Attestation Engagements (SSAE). The ASB is issuing the clarified attestation standards as SSAE 18. The old AT sections in AICPA Professional Standards remains effective through April 2017.