The manager of the payroll department requested a review of the payroll process, but only...

The review requested by the manager of the payroll department, focusing solely on the processes related to the approval of time worked, is best classified as a Compliance Assurance Engagement. This type of engagement aims to ensure that specific processes comply with established policies, procedures, or regulations — in this case, those related to payroll approvals. The emphasis on adherence to established guidelines and rules characterizes this as a compliance engagement rather than financial, operational, or risk management consulting.

IIA guidance on different types of audit engagements.