Which of the following is critical for an IS auditor to review in regards to a vendor's service level agreement?

The review of agreed-on key performance indicators (KPIs) is critical for an IS auditor examining a vendor's service level agreement (SLA) because KPIs provide measurable standards that clarify the expected performance levels of the vendor's services. These indicators allow the organization to assess whether the vendor is meeting the agreed-upon performance criteria, which is vital for maintaining service quality and ensuring that the business objectives are met.

In the context of vendor management, KPIs help in outlining specific metrics such as uptime percentages, response times, and resolution times for issues, thus enabling the organization to hold the vendor accountable. This not only supports performance tracking but also establishes a basis for discussing potential penalties or corrective actions if the vendor fails to meet the standards set in the SLA.

While compliance with the master contract, audit clauses, and results of independent audits are important aspects of the overall vendor risk management and compliance framework, they do not specifically address the operational performance that KPIs do. Therefore, understanding and monitoring the KPIs forms a crucial part of the IS auditor's responsibilities in ensuring effective vendor management and service delivery.