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 |
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 |
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.