Root cause analysis

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Root cause analysis (RCA) is a class of problem solving methods aimed at identifying the root causes of problems or events. The practice of RCA is predicated on the belief that problems are best solved by attempting to correct or eliminate root causes, as opposed to merely addressing the immediately obvious symptoms. By directing corrective measures at root causes, it is hoped that the likelihood of problem recurrence will be minimized. However, it is recognized that complete prevention of recurrence by a single intervention is not always possible. Thus, RCA is often considered to be an iterative process, and is frequently viewed as a tool of continuous improvement.

RCA, initially is a reactive method of problem detection and solving. This means that the analysis is done after an event has occurred. By gaining expertise in RCA it becomes a pro-active method. This means that RCA is able to forecast the possibility of an event even before it could occur.

Root cause analysis is not a single, sharply defined methodology; there are many different tools, processes, and philosophies of RCA in existence. However, most of these can be classed into five, very-broadly defined "schools" that are named here by their basic fields of origin: safety-based, production-based, process-based, failure-based, and systems-based.

Despite the seeming disparity in purpose and definition among the various schools of root cause analysis, there are some general principles that could be considered as universal. Similarly, it is possible to define a general process for performing RCA.


[edit] General principles of root cause analysis

  1. Aiming performance improvement measures at root causes is more effective than merely treating the symptoms of a problem.
  2. To be effective, RCA must be performed systematically, with conclusions and causes backed up by documented evidence.
  3. There is usually more than one potential root cause for any given problem.
  4. To be effective the analysis must establish all known causal relationships between the root cause(s) and the defined problem.
  5. Root cause analysis transforms an old culture that reacts to problems to a new culture that solves problems before they escalate, creating a variability reduction and risk avoidance mindset.

[edit] General process for performing and documenting an RCA-based Corrective Action

Notice that RCA (in steps 3, 4 and 5) forms the most critical part of successful corrective action, because it directs the corrective action at the root of the problem. That is to say, it is effective solutions we seek, not root causes. Root causes are secondary to the goal of prevention, and are only revealed after we decide which solutions to implement.

  1. Define the problem.
  2. Gather data/evidence.
  3. Ask why and identify the causal relationships associated with the defined problem.
  4. Identify which causes if removed or changed will prevent recurrence.
  5. Identify effective solutions that prevent recurrence, are within your control, meet your goals and objectives and do not cause other problems.
  6. Implement the recommendations.
  7. Observe the recommended solutions to ensure effectiveness.
  8. Variability Reduction methodology for problem solving and problem avoidance.

[edit] Root cause analysis techniques

  • Cause and effect analysis A technique that orgainizes the analyst's knowledge into a cause and effect chain. For every effect there is a cause. There is a fairly long chain of relationship between the cause and its effect. In theory, if the lowest cause on the chain is removed, the problem will not re-appear. Root Cause is a variability reduction methodology for problem solving and problem avoidance. Root cause mindset transforms an old culture that reacts to problems to a new culture that solves problems before they escalate, creating a cost effective variability reduction and risk avoidance mindset.
  • 5 Whys
  • Kepner-Tregoe Problem Analysis - a root cause analysis process developed in 1958, which provides a fact-based approach to systematically rule out possible causes and identify the true cause
  • Failure mode and effects analysis Also known as FMEA.
  • Pareto analysis
  • Fault tree analysis
  • Bayesian inference
  • Ishikawa diagram, also known as the fishbone diagram or cause and effect diagram
  • Cause Mapping - A problem solving method that draws out, visually, the multiple chains of interconnecting causes that lead to an incident. The method, which breaks problems down specific cause-and-effect relationships, can be applied to a variety of problems and situations
  • 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.
  • Event and Causal Factor Charting - Another technique, where each event is enclodsed in a rectangle. A series of Events are enclosed in rectangles with lines inter connecting the rectangles. Events progress from Left to Right, just like in a text. Striking of a match Stick is an event. If there is possibility of the interconnection the rectangles are connected with the dotted lines. The 'Cause' are identified for each event. In order to diffrentiate the Cause with Events, Cause are enclodes in Ellipse. The 'Presence of inflammable Gases' can be a 'Cause'. Both 'Event' and 'Cause' put to-gether may lead to the accident e.g 'Explosion'.
  • TapRooT - A structured root cause analysis system built around a problem solving process with six embedded techniques to guide investigators beyond their current knowledge to the root causes of human performance and equipment failure related incidents.
  • ARCA; Apollo Root Cause Analysis - A unique problem solving process characterized by a structured cause and effect chart known as a Realitychart which allows all problem stakeholders to own the problem and its corrective actions.
  • RPR Problem Diagnosis - An ITIL-aligned method for diagnosing IT problems.

Common cause analysis (CCA) common modes analysis (CMA) are evolving engineering techniques for complex technical systems to determine if common root causes in hardware, software or highly integrated systems interaction may contribute to human error or improper operation of a system. Systems are analyzed for root causes and causal factors to determine probability of failure modes, fault modes, or common mode software faults due to escaped requirements. Also ensuring complete testing and verification are methods used for ensuring complex systems are designed with no common causes that cause severe hazards. Common cause analysis are sometimes required as part of the safety engineering tasks for theme parks, commercial/military aircraft, spacecraft, complex control systems, large electrical utility grids, nuclear power plants, automated industrial controls, medical devices or other safety safety-critical systems with complex functionality.

[edit] Basic elements of root cause

  • Materials
    • Defective raw material
    • Wrong type for job
    • Lack of raw material
  • Machine / Equipment
    • Incorrect tool selection
    • Poor maintenance or design
    • Poor equipment or tool placement
    • Defective equipment or tool
  • Environment
    • Orderly workplace
    • Job design or layout of work
    • Surfaces poorly maintained
    • Physical demands of the task
    • Forces of nature
  • Management
    • No or poor management involvement
    • Inattention to task
    • Task hazards not guarded properly
    • Other (horseplay, inattention....)
    • Stress demands
    • Lack of Process
  • Methods
    • 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
    • 4ME (Man, Machine, Materials, Method and Environment)is for me for root cause analysis.

[edit] Also see

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