Operating Effectiveness
Definition
The assessment of whether a control has consistently functioned as designed over the audit period. Requires evidence of actual operation, such as logs, approval records, or re-performance of the control, and usually involves sampling from the full population of control executions.
- Question answered
- Did the control actually function as designed over time
- Distinct from
- Design effectiveness (whether the control could work in theory)
- Evidence used
- Logs, approval records, re-performance
- Method
- Sampling from the population of control executions
Common questions
Why can a well-designed control still fail an operating effectiveness test?+
A control can be correctly designed on paper but skipped under deadline pressure, applied inconsistently by different staff, or overridden by management, none of which shows up until the auditor samples actual execution records rather than just the policy document.
How large a sample is typically needed to test operating effectiveness?+
Sample size depends on how frequently the control operates and the auditor's desired confidence level; a daily control run hundreds of times a year needs a larger sample than an annual control, and auditing standards provide sampling tables rather than a single fixed number.
Related terms
- Audit Chain of Custody
- The documented record of when audit evidence was collected, by whom, from what source, and how it has been stored and accessed...
- Control Criterion
- The standard against which a control is evaluated. Criteria may come from an external standard (ISO 27001 Annex A, NIST CSF, PCI-DSS),...
- Design Effectiveness
- The assessment of whether a control is designed in a way that would prevent or detect the risk it targets, if it...
- Document Control
- The systematic management of all procedural documents in a quality management system, ensuring that the current approved version is in use, all...
- Evidence Sufficiency
- The standard that evidence must meet to support an audit conclusion. Evidence must be relevant to the control being tested, reliable in...
- Fieldwork
- The active evidence-gathering phase of an audit, during which the auditor applies testing procedures to specific controls and collects the evidence that...
- Information Security Policy
- A high-level governance document that states what the organisation intends to achieve in protecting information, assigns accountability to roles, and sets the...
- Policy Exception
- A formal, time-bounded approval to deviate from a policy or standard requirement when the standard control is not achievable. Exceptions must be...
- Procedure
- A step-by-step operational instruction that tells a specific role how to carry out a task in conformance with the relevant standard. Procedures...
- Standard
- A document that translates a policy requirement into specific, measurable criteria. For example, a password policy may require strong authentication; the accompanying...
Explained in these topics
- Fieldwork, Evidence Collection, and Control Testing
- Information Security Policy HierarchyWhether a control is actually performing as the policy and standard require, as opposed to merely being documented (design effectiveness). Auditors test operat...