Root cause analysis methods

Rahul Kashyap
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Root cause analysis methods
Purpose
To lay down the procedure and guidance for conducting investigation of various non-conformities at manufacturing site to identified the root cause and recommend the correction and preventive action.
Scope
The scope of this SOP is to provide the procedure for Root Cause Analysis.
Procedure
Preamble
Non Conformity:
Any non-conformance which is departure form a standard procedure, specification shall be considered as non-conformity. This includes but not limited to; System failure, Equipment failure, Batch failure, Market Complaint, Deviation, Stability failure, OOS (Full Form-Out of Specifications) results, OOT (Full Form-Out of Trends) results, out of calibration, Annual product quality review and non- conformance related to regulatory / customer requirements, Product or Process not meet standard acceptance limits.
Immediate Action:
Action taken immediately to salvage the situation and to prevent the nonconformity to spread further. Immediate action may involve some remedial action.
Remedial Action:
Action taken to improve a situation and to fix or correct a nonconformity, and return the process, product, or materials to an acceptable status of control of quality.
Corrective Action:
Action to eliminate the cause of detected non-conformity. Corrective Action is taken to prevent the reoccurrence.
Preventive Action:
Action to eliminate the cause of a potential non-conformity. Preventive Action is taken to prevent the occurrence.
Major Impact:
Any nonconformity condition that has the potential to impact on safety, quality, identity, purity or strength of an affected item.
Minor Impact:
Any nonconformity condition that does not have the potential impact on safety, quality, purity, identity or strength of an affected product / material.
Root Cause:
The underlying reason for the non-conformance which is confirmed by evidence of a known sequence of event and observations.
Most Probable Cause:
A most likely root cause that cannot be established beyond doubt, but is adequately and substantially supported by data collected during the investigation with the application of sound and logical approaches.
A most probable cause is identified through investigation, in case where the level of certainly required to establish the root cause could not be reasonably determined.
Investigation Report:
Report on each nonconforming conditions which provide and lists the non-conformance or deviation, items affected, investigation details covering root cause analysis & impact assessment, disposition, corrective action, preventive action and evidence of closure for the nonconformance.
Root cause analysis (RCA) shall  be  done  to  identify  the  root cause after  nonconformance has  occurred.
Following are the instances where root cause analysis may be performed but not limited to;
Internal: OOS  reports, Self-inspection  observation,  Deviations,  Trends analysis, Batch  Failures, Non  Conformance & Annual Product Quality Review  etc.
External: Market Complaints, Quality Audits Report, Field Service Report, etc.
Head QA/ Designee shall assign RCA team members from applicable department. RCA team shall involve who are most familiar with the process and system on the basis of experience and knowledge. Also the concern department Head and Quality assurance shall be the part of RCA team.
Following shall be the requisites for performing RCA:
Basic knowledge and experience for handling incident and investigation.
Understanding of process and systems.
Gathering data from Man, Machine, Method Material, Measurement & Mother Nature.
Analysis of data for all causal factors.
Use of appropriate RCA tools.
Determination of root cause for each causal factor.
CAPA, its implementation and continual improvement.
Tools to be used in RCA:
          Fish bone diagram / Ishikawa Diagram /Cause and Effect Diagram
          5 Why Analysis
          Brainstorming
Fish bone diagram / Ishikawa diagram / Cause and effect diagram: 
This tool shall be used in case of nonconformance triggered from multiple root cause   or multidirectional or need to display and explore many possible causes of a specific problem / condition. The fish bone diagram is aim to generate possible causes for the problem and then narrowing focus into the most probable cause for the problem.
Stage:
          Define the problem.
          Categorize the cause and Brain Storm the main cause (6Ms).
          Identify the most likely causes.
          Priorities the causes based on severity i.e. the most probable cause.
          Proposed the corrective action and preventive action.

Root Cause Analysis 6M Procedure
Root Cause Analysis 6M

    

                                                                                  
These 6Ms are Man power (Physical work), Machine (Technology), Method (Process), Material (Includes raw & packing material), Measurement (Inspection) and Mother Nature / Milieu (Environment).
The above causes are the most significant causes, or potential causes of the problem.  These will form the main branches from the “Backbone Arrow” any additional causes   identified shall be included as a separate category, if required.
From these, continuous to brainstorm in more detail, and explore why these factors           may be problem.  It is best to develop as many hypotheses as so that no potential root   cause is overlooked.
In case fish bone diagram, for defining sub causes, refer “Sub Cause Identification Form” In this annexure, 6M’s causes are identified along with applicable question.  Each question need to be in the form of 'Yes', ‘No’ and Not applicable. Any more questions apart from questions defined can be written in blank space provided under each cause. These causes should be considered as most likely causes.
NOTE:   Whenever causes  other  than  6 M  are  identified,  same shall  be evaluated  as mentioned above as per “Sub Cause Identification Form”.
Example for Cause/ Reasons of nonconformance that may be identified by performing RCA are as follow:
Man” may include but not limited to, Unauthorized to operate, Unskilled and untrained, insufficient number of people, not following procedure, role and responsibility of people & training  etc.
Machine/ Equipment” may include but not limited to, Incorrect tool selection, Poor maintenance or design, Defective equipment or tool, Out of calibration, Inappropriate capacity & recent changes etc.
Method/ Process” may be include but not limited to, No or poor procedures,  Practices are not the same as written procedures, Poorly communicated not validated, critical control points, robustness of the process, validated method & deviation in execution etc.
Materials” may include but not limited to, Defective material, Wrong material,   contaminated material, Mix-up  in material from unapproved source,  inappropriate sampling and testing, test results at incoming stage, material packing, storage conditions, quality trends & vendor status etc.
Measurement  may include  but not  limited  to, Procedure not  followed, Practices  are not the same as written procedures, measuring technique  not validated, frequency of inspection & execution of methodology etc.
Mother Nature” may include but not limited to, Improper maintenance of temperature, Humidity conditions, Storage conditions during transportation etc.
RCA summary report shall be prepared as per “Investigation Summary Report”, the sub causes identified as per “Sub Cause Identification Form”, which are further to be subjected to 5-why analysis are to be considered as most likely causes.
Look for those items that appear in more than one category. This shall be evaluated by RCA team member. These become the most probable causes.
From those items identified as the most probable causes the team shall reach a consensus using the team's best collective judgment on listing those items being the most probable causes.
During evaluation, team shall be priorities the causes as per the severity and same shall be recorded in “Investigation Summary Report”.
After approval of the RCA report from Head QA/Designee, proposed corrective and preventive action against identified root cause shall be initiated. If required, CAPA shall be logged for execution of the proposed corrective and preventive actions as per SOP of CAPA.
5 Why analysis: 
This tool shall be used in case of nonconformance triggered from single cause or unidirectional, incident involving human factor or obvious error.
Investigator shall carry out the investigation based on “5-Why” and shall keep asking the question “Why?” for non-conformance until the contributing factor underlying the problem is not identified.
RCA team shall ask series of “whys” repeat this with each major cause to produce sub causes. Continue asking “why's” and classify them on the diagram. If an idea fits on more than one branch place it on both. Be sure that the cause has a direct, logical relationship to the problem or effect.
Continue until potential root causes has been identified.  A root cause is one that can explain the “effect” and if removed would eliminate the problem.
Stages:
          Write down the specific problem.
          Ask why the problem happened and write down the answer below the problem.
          If the answers written in first instance documents not identify the root cause of the problem, then again repeat the question why and again write down the answer.
          Repeat this exercise until the investigation team is agreement that the root cause is identified.
Root Cause Analysis Method
Root Cause Analysis
Investigation shall be performed as per “5-Why Analysis”

Brain Storming:
Investigation shall be done by brain storming process. Every possible idea shall be captured to find a conclusion for specific problem.
List of ideas shall be gathered from all personnels involved in investigation.
All possible causes/assumptions/hypothesis shall be thought upon during investigation by this tool.
 Brain storming investigation shall be performed.
Evaluation and Disposition:
Evidence of completion of CAPA with supporting data and reference shall be provided. Summary for the same shall be appended in the CAPA register.
Head QA shall dispose the investigation report, once the action proposed are executed.
The report must be organized, details, include all attachments.
Follow-Up
The root cause analysis and proposed CAPA shall be periodically followed-up for the effective implementation of CAPA to overcome the re-occurrence of Non-conformances.
CAPA shall be assessed for the adequacy of practical implementation.
The CAPA implementation shall be re-checked based on effective monitoring. If found adequate or effective, the same shall be implemented through change control, as applicable.
If CAPA is found not effective, the CAPA shall be re-reviewed based on outcome of the follow-up and further action plan to be proposed.

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