Operational assurance is confidence that a security control works reliably in live operations, not just in a policy, diagram, or test environment. It asks a practical question: can this process keep doing its job under normal pressure, over time, with real users, systems, and failures?
This matters because many attacks succeed when defenses exist only on paper. An access review, backup routine, alerting rule, or incident workflow may look complete in a document set, but operational assurance requires evidence such as logs, test results, audit trails, and repeated execution. Defenders use it to prove that controls are monitored and maintained; attackers try to exploit the gap between stated security and actual behavior. In regulation and assessments, operational assurance is often the difference between being compliant and being merely documented.