The number of emergency change requests is the most important factor to review when confirming whether implemented controls are operating effectively, as it indicates the frequency and severity of incidents or issues that require urgent changes to the controls, and may reflect the control deficiencies or failures. The results of benchmarking studies, the results of risk assessments, and the maturity model are not the most important factors, as they are more related to the comparison, evaluation, or improvement of the controls, respectively, rather than the confirmation of the control effectiveness. References = CRISC Review Manual, 7th Edition, page 154.