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Monday, October 15, 2007

Tool's for the toolbox, The Deming Cycle and RCA

PDCA ("Plan-Do-Check-Act") is an iterative four-step problem-solving process typically used in quality control. It is also known as the Deming Cycle


Establish the objectives and processes necessary to deliver results in accordance with the specifications.

Implement the processes.
Monitor and evaluate the processes and results against objectives and Specifications and report the outcome.
Apply actions to the outcome for necessary improvement. This means reviewing all steps (Plan, Do, Check, Act) and modifying the process to improve it before its next implementation.


Root cause analysis (RCA) is a class of problem solving methods aimed at identifying the root causes of problems or events.

General principles of root cause analysis
Aiming corrective measures at root causes is more effective than merely treating the symptoms of a problem.
To be effective, RCA must be performed systematically, and conclusions must be backed up by evidence.
There is usually more than one root cause for any given problem.

General process for performing root cause analysis
Define the problem.
Gather data/evidence.
Identify issues that contributed to the problem.
Find root causes.
Develop solution recommendations.
Implement the recommendations.
Observe the recommended solutions to ensure effectiveness.

Root cause analysis techniques
5 Whys
Failure mode and effects analysis
Pareto analysis
Fault tree analysis
Bayesian inference
Ishikawa diagram, also known as the fishbone diagram or cause and effect diagram
Barrier analysis - a technique often used in particularly in process industries. It is based on tracing energy flows, with a focus on barriers to those flows, to identify how and why the barriers did not prevent the energy flows from causing harm.
Change analysis - an investigation technique often used for problems or accidents. It is based on comparing a situation that does not exhibit the problem to one that does, in order to identify the changes or differences that might explain why the problem occurred.
Causal factor tree analysis - a technique based on displaying causal factors in a tree-structure such that cause-effect dependencies are clearly identified.

Basic Elements of Root Cause

Defective Raw Material
Wrong type for job
Lack of raw material
Incorrect tool selection
Poor maintenance or design
Poor equipment or tool placement
Defective Equipment or tool
Orderly workplace
Job design or layout of work
Surfaces poorly maintained
Physical demands of the task
Forces of Nature
No or poor management involvement
Inattention to task
Task hazards not guarded properly
Other (horseplay, inattention....)
Stress demands
No or poor procedures
Practices are not the same as written procedures
Poor communication
Management System
Training or education lacking
Poor employee involvement
Poor recognition of hazard
Previously identified hazards were not eliminated

Have fun, anyone wanting to know more drop me mail



1 comment:

Joe Jordan said...

A sound explanation of proven methodologies for getting to the root cause of a problem. One can only wish that more companies would take time to identify the true cause of a problem before implementing a dozen ways to try to fix the symptoms.

Perhaps the most under-used question in business is "What changed?" If those charged with resolving performance deviations would take the time to answer that question first, they could save themselves hours of chasing possible causes that have little if anything to do with the root cause of a business challenge.