Residualiriski

Residualiriski, often translated as residual risk, is the level of risk that remains after risk controls and mitigation measures have been applied. It is a central concept in risk management, used to distinguish the risk that exists before controls (inherent risk) from the risk that remains once controls are in place. The magnitude of residualiriski depends on how effective the controls are, how precisely risk is assessed, and the organization’s risk appetite. It acknowledges that it is usually impossible to eliminate all risk.

In practice, residualiriski is estimated by applying the expected risk reduction from implemented controls to the inherent risk. Organizations typically record residualiriski in a risk register, including the risk description, inherent level, implemented controls, residual level, risk owner, and tolerance. Residualiriski should be monitored and reviewed regularly, and reassessed after significant changes, incidents, or control failures. Decision makers may choose to accept, further mitigate, transfer, or avoid residualiriski based on cost, feasibility, and risk appetite.

Applications span many domains, including information security, finance, and project management. In information security, residualiriski represents the remaining threat after controls such as access management, encryption, and monitoring are applied, highlighting areas like phishing, human error, or zero-day exploits. In project or operational contexts, residualiriski may include schedule delays, supply chain disruptions, or regulatory changes that persist despite planning and controls.

Standards and frameworks such as ISO 31000, ISO 27001, and NIST guidance address the concept of residualiriski as part of risk assessment, treatment, and ongoing governance.