Operationally verifiable means a security control is proven to work in real operations, not just described in a policy, audit note, or compliance checklist. A control is operationally verifiable when defenders can demonstrate it repeatedly, with normal staffing, handovers, and real constraints, and when it still functions during disruption.
This matters because attackers exploit gaps between paperwork and practice. A policy may say alerts are reviewed, backups are tested, or incidents are escalated, but if those steps depend on one person or an informal habit, the defense can fail under pressure. In mature security programs, operationally verifiable controls are exercised, logged, and measurable: for example, recovery tests, access reviews, incident drills, and documented fallback procedures. Regulators and auditors look for this evidence because real resilience is shown by repeatable execution, not by written intent alone.