Residual Risk: if you’re not familiar with the term, you should learn how it applies to your Business Continuity Management program.

In pulmonary science (the study of lungs) there’s something called ‘residual volume’.  That’s the amount of air that remains in your lungs after you forcefully exhale.  No matter how hard you try, there will always be residual volume.

In Business Continuity Management there’s something called ‘residual risk’.  It’s not much different: once you’ve mitigated identified risks, what’s left is residual risk.  No matter what you do, there will always be residual risks.  Business Continuity Plans are the primary tactic to deal with those residual risks.

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http://ebrp.net/residual-risk-a-key-business-continuity-concept/