Corrective vs. Preventive Action by Russ Westcott

uality professionals frequentlyexpress confusion as to the dif-ference between corrective and

preventive action. A corrective actiondeals with a nonconformity that hasoccurred, and a preventive actionaddresses the potential for a noncon-formity to occur. Many ISO 9000 regis-trar auditors tell their clients to useseparate procedures and forms to doc-ument each type of action. Nothing inthe standard says this must be done,but p. 13 includes the word preventin the clauses on corrective and pre-ventive action.

On closer reading, however, section8.5.2 says corrective action eliminatesthe cause of nonconformities to preventrecurrence, and section 8.5.3 says pre-ventive action determines and elimi-nates the causes of potential noncon-formities to prevent occurrence. See,there is a difference!

Common Misconceptions

There are three common misconcep-tions about corrective and preventiveaction:

1. The standard calls for document-ing every occurrence of a non-conformity.

2. A preventive action is really justcalling a corrective action some-thing different.

3. The major reengineering of aprocess, product or service, or theintroduction of a new process orequipment, is not a candidate forpreventive action documentation.

One way to dispel these is by sepa-rating situations into what I call apatch (a single occurrence of a noncon-formity that involves little risk andneeds not be recorded), a correctiveaction (a more serious nonconformityinvolving some risk that requiresaction to prevent recurrence and mustbe recorded), a preventive action (aprocess that can be improved to pre-vent occurrence of a nonconformityand is to be documented) or a develop-mental action (a planned change tointroduce a new process or product inresponse to strategic objectives, docu-

mented as a preventive action).Consider the examples in Table 1. (Goto www.asq.org, and click on thecover of Quality Progress.)

Corrective Action Process

Locate and document the rootcause of the nonconformity.

Scan the entire system to ensureno other similar nonconformitycould occur.

Analyze the effect such a noncon-formity may have had on a prod-uct or service produced before thenonconformity was discovered,and take action appropriate to theseverity of the situation by eitherrecalling the product, notifyingthe customer, downgrading orscrapping product.

Establish thorough follow-up toensure the correction is effectiveand recurrence has been prevented.

Preventive Action Process

Take proactive steps to ensure apotential nonconformity does notoccur.

Employ process and system analy-sis to determine how to build insafeguards and process changes toprevent nonconformance. Forexample, use a failure mode andeffects analysis to identify risksand potential deficiencies and toset priorities for improvement.

Developmental Action Process(Treated as Preventive Actions)

Initiate an improvement project,with project plans, justification forplanned expenditures, resourcecontrols and evaluation.

Contain a related series of actions,often separated by long periods

104 I MARCH 2005 I www.asq.org

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Knowing the difference could makeall the difference.

so you can wait and see progressand results.

Use a variety of appropriate dis-ciplines at different times duringthe project.

Establish a means for communi-cating what has been done andwhat has to be done to facilitatecommunication about changes toproject team members.

Include a clear trail of actionstaken and decisions made to sub-stantiate the decision to proceed,document lessons learned andavoid needless reinvention onfuture similar projects.

Documenting and controlling cor-rective and preventive actions ensureappropriate action is taken within areasonable timeframe and the result-ing changes work.

BIBLIOGRAPHY

ANSI/ISO/ASQ Q9001-2000 Quality Man-agement SystemsRequirements, ANSI/ASQ, 2001.

Robitaille, Denise, The Corrective ActionHandbook, Paton Press, 2002.

Stamatis, D.H., Failure Mode Effect Analysis:FMEA From Theory to Execution, secondedition, ASQ Quality Press, 2003.

RUSS WESTCOTT is president of R.T. Westcott& Associates, Old Saybrook, CT. He is a Fellowof ASQ and an ASQ certified quality auditor andquality manager. Westcott serves on several com-mittees of ASQs Quality Management Divisionand is a certified quality manager refresher courseinstructor. He is co-editor of several QualityPress books, including The Certified QualityManager Handbook and The QualityImprovement Handbook, and author ofSimplified Project Management for QualityProfessionals.

BACK TOBASICS

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BACK TOBASICS

Situation Frequency Suggested action Type Comment

Final inspectionreturns part to operator to cor-rect. Correctedpart returned tooriginal lot.

Single occur-rence beforeshipment.

Rework, repair. Patch. May not need torecord; depends onmagnitude of risk and frequency.

Item or work unus-able.

Single occur-rence beforeshipment.

Scrap. Patch. May not need torecord; depends onmagnitude of risk andfrequency.

Item or servicedoes not meet customer require-ments.

Serious.Occurred more than once and after shipment.

Assign for action(and contact customer, asappropriate): Find root cause. Correct. Document. Evaluate

effectiveness.

Corrective action.

Situation thatcould potentiallyaffect process,product or serviceis found.

Nothing has occurred, yet.

Assign for action: Analyze what ifs. Evaluate poten-

tial effects offailure.

Identify solution. Implement

solution. Document. Evaluate

effectiveness.

Preventive action. May require long-term follow-up toensure effectiveness.

Desire to improvethe process, prod-uct or service forreasons other thannonconformance.

No nonconfor-mance exists,and no poten-tial for one isdetected.

Assign project: Analyze present

process. Reengineer

process. Document

process. Evaluate effec-

tiveness ofreengineeredprocess.

Developmentalaction. Use preven-tive action systemwith project man-agement.

Organizations fre-quently forget to takecredit for this type ofbreakthrough pro-ject.

Four Types of ActionTABLE 1