Blog, ISO Compliance

Cause and Effect – Fish Bone Diagram

Training your employees to report problems in a timely manner is important.  Once the problem has been identified, a document a clear description of the problem to include the product part number, lot number, quantity, time period, manufacturing operation and other descriptive information so that the non-conforming material can be identified and quarantined.  It is clearly time to conduct a root cause analysis using the Cause and Effect – Fish Bone Diagram.

Clearly state the actual non-conforming condition and data as well as including the specification and tolerance range which the product failed to meet.  Complete all necessary paperwork to document the non-conformance following your company’s standard operating procedure.  Clearly documenting in the non-conformance in a Corrective and Preventive Action Report (CAPA) will aid in the investigation and disposition of product.

Conduct a brainstorming session with the manufacturing, engineering and quality personnel who may have knowledge regarding the process or product to identify possible causes for the problem.  Using a fishbone diagram can help focus on the critical criteria to consider (eg: Machines, Methods, Materials, Measurements, Mother Nature (Environment), and Manpower (People).  Conducting a thorough root cause analysis is critical. Based on the brainstorming session, each possible cause needs to be investigated to determine a solution.  Asking the five “why’s” often gets to the root of the problem.

Cause and Effect Diagram

Often times there are more than one root cause or a combination of causes between machines and methods or people and measurements, etc.  Root causes can be reviewed to determine the top priority based on risk.   Once the causes are identified, solutions must be put into place.  A good rule of thumb would be to complete investigations within 30 days.  After 30 days, information and recollections of events becomes diluted.  Root causes and corrective actions should be documented into the CAPA investigation plan with assigned responsibilities and timelines.


cause and effect

Follow up is the key to success.  Determining the effectiveness of the corrective actions will determine if the root cause analysis and corrective actions implemented were effective.  Effectiveness can be determined by measurement, trending, inspection, validation, or outside verification.

Keeping management involved and informed of the corrective and preventive problem solving process will ensure support in your organization.  The Corrective and Preventive Action system should be a topic for discussion at management review.  Maintaining an effective CAPA system plays ensures the effectiveness of the ISO 9001 Quality Management System in your organization.

Enjoy the World of “Q”

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