Preventive Action, Corrective Action and Correction

What's the difference between corrective action and preventive action? Are separate procedures required by ISO 9001?

The corrective action process is a problem-solving process and the preventive action process is a risk-analysis process.

Corrective action

Corrective action is defined in ISO 9000 as "action taken to eliminate the cause of a detected nonconformity or other undesirable potential situation" and notes that corrective action is taken to prevent recurrence. ISO 9000 also points out that corrective action differs from correction.

Correction is defined in ISO 9000 as "action to eliminate a detected nonconformity". Put simply, if something has gone wrong then the action you take to fix that instance is correction. For example, if a part comes off the production line with a screw missing, then putting the missing screw back is correction. The action you take to stop it happening again is corrective action. Using the same example, making sure the correct number of screws are supplied for each part would be corrective action. It gets confusing when that is referred to as preventing a recurrence. In ISO 9000 terminology that action is not preventive.

There has to be a problem for you to take corrective action. If no problem exists but there is a possibility that a problem might occur, preventing that potential problem is preventive action.

Preventive action

Preventive action is defined in ISO 9000 as "action taken to eliminate the potential causes of a nonconformity or other undesirable potential situation". ISO 9000 distinguishes preventive action from corrective action by noting that "preventive action is taken to prevent occurrence" as opposed to recurrence which characterises corrective action. In the example used above, planning the production of the part to ensure that all the screws are fitted would be preventive action.

A risk management process is a good example of preventive action. Assessing the impact and likelihood of a risk occurring and taking action to prevent occurrence is preventive action.

Other examples of methods for identifying potential nonconformities are:

• trend analysis for process and product characteristic (where a worsening trend indicates a potential problem)
• monitoring of customer feedback
• evaluation of problems in similar processes or products
• planning of new processes and products
  

Procedure Requirements

On the question of procedures, ISO 9001:2008 makes it clear that although a procedure is required for corrective action and a procedure is required for preventive action. There is no stipulation that these should be separate documents (see the NOTE 1 under 4.2.1 in the standard). However, the combination of a corrective action procedure and a preventive action procedure into a single document is not recommended as it then becomes more difficult to clearly separate the two distinctly different approaches. You may also find it difficult to demonstrate to an external assessor that the processes are separate and that you actually perform both types of action.

Note that in the above discussion, reference is made to ISO 9000 and not ISO 9001. ISO 9000 contains the concepts and terminology on which ISO 9001 is based and is essential reading to gain a full understanding of ISO 9001.