1. As to level of assurance:
• Reasonable Assurance – the objective is a reduction in assurance engagement risk to an acceptably low level as the basis for a positive form of expression of a practitioner’s conclusion. (e.g., audit of historical procurement records)
• Limited Assurance – the objective is a reduction in assurance engagement risk to a level that is acceptable in the circumstances of the engagement, but where the risk is greater that for a reasonable assurance engagement, as the basis for a negative form of expression of the practitioner’s conclusion. (e.g., review of historical procurement records
2. As to structure of engagement:
• Assertion-based – the evaluation or measurement of the subject matter is performed by the responsible party, and the subject matter information is in the form of assertion to the intended users.
• Direct Reporting – the practitioner either directly performs the evaluation or measurement of the subject matter, or obtains a representation from the responsible party that has performed the evaluation or measurement that is not available to intended users. The subject matter information is provided to the intended users in the assurance report.