Which key performance efficiency IKPI) BEST measures the effectiveness of an organization's disaster recovery program?

The number of SLA violations is a broad metric that may be influenced by many factors beyond disaster recovery effectiveness, making it an imprecise measure for the program itself.

The percentage of recovery issues identified during an exercise measures the effectiveness of the exercise in finding flaws, not the ultimate effectiveness of the recovery program in meeting recovery goals.

The number of total systems recovered within the Recovery Point Objective (RPO) is less effective than RTO for measuring program effectiveness because RPO focuses on data loss tolerance (data age), while RTO focuses on service availability, which is the primary objective of disaster recovery.

The percentage of critical systems recovered within the Recovery Time Objective (RTO) is the best KPI because it directly measures the program's ability to restore essential business functions within an acceptable timeframe post-disaster. RTO focuses on the time-criticality of services, and 'critical systems' ensures the most important assets are prioritized, reflecting true business impact and recovery success.