Definition
An action taken against a problem that has already occurred with the aim of removing its root cause; it must follow root cause analysis and be verified against recurrence, otherwise it is only containment.
In detail
Corrective action and countermeasure are used interchangeably in the courseware, but the emphasis differs: countermeasure distinguishes temporary from permanent, corrective action insists on addressing the root cause and standing up to a recurrence check. It pairs with preventive action — corrective for what has happened, preventive for what has not — and together they form corrective and preventive action. Three questions test one: which root cause does it remove, when is recurrence verified, and who escalates if it fails. Actions that change only people (more training, more awareness) are almost never corrective actions.
Example in practice
A machine failure recurs three months running and the five-why sheet traces it to a lubrication point missing from the standard. The corrective action revises the TPM manual and check sheet and retrains the team; only after thirty days with the point clean and no recurrence is the item closed.