Root cause - method or myth?
How often have you heard:
We found the root cause of the incident and have fixed it!
However, modern thinking and methodologies recognise that there is no such thing as one root cause and that incidents are caused by multiple interacting contributory factors.
This article explores a number of methodologies including the traditional cause and effect fishbone diagram, or Iskikawa diagram, which can be used as the technique for incidents with minor incident or injury potential. Once used, the 5 – Whys can be applied to the causal factors prior to actions being identified. This prevents the focus on identifying only one root cause. Investigative methodologies such as Incident Cause Analysis Method (ICAM) are required for more serious/complex incidents.
Should we only comprehensively investigate incidents where there is serious harm?
Incidents are often classified based on the actual consequence / outcome as opposed to their potential (what could have happened not just what did) to determine severity and this may not influence the type or complexity of investigation. As the difference between a minor and a very serious incident can be a matter of chance, incident investigation “should be driven by the type of accident events to prevent accidents from (re-)occurring in the future, regardless of their outcome. Therefore, the concept of potential should be introduced and this should be used to determine the depth and breadth of investigation.
All hazards, incidents and near misses should be reported and investigated, with escalation in reporting and composition of the investigation team dependent on the potential and actual severity of the incident (minor or serious), resultant injury and whether the incident was notifiable, as defined by section 37 of the Victorian Occupational Health and Safety Act 2004 (OHS Act, 2004).
Investigative methodologies must distinguish between the severities of incidents. The investigative method utilised should match the complexity of the incident being investigated and be able to be adapted or a range of tools or models made available that can be selected based on their adequacy to complete the level of investigation required.
PEEPO
PEEPO is an example of a complex linear model in that causes under each heading are considered independently as opposed to focussing on any sequential interaction, as is the case with James Reason’s Swiss Cheese Model. It is focused on finding the cause of the actual event that has taken place to prevent its reoccurrence as opposed to any related potential events or outcomes.
Example of a Fishbone Diagram
An adaption of the cause and effect fishbone diagram or Iskikawa diagram, PEEPO is not intended to be a complete investigation tool in itself but the first step in an ICAM of investigation which is the data collection aspect. The technique combines brainstorming with a type of mind map (a non-linear diagram with tasks, words, concepts etc. linked around a central concept) and seeks to identify all possible causes of an incident by focussing on the pre-selected factors; Physical, Environment, Equipment, People and Organisational. Unlike a traditional fishbone diagram where possible incident causes are grouped by factor(s) and the potential outcome is indicated on the diagram, PEEPO is typically represented just to include lists of anything relevant to each of the factors and is meant to be used as a planning tool to provide guidance and direction for the investigation team.
It requires further data analysis and investigation to determine the most relevant aspects and the critical contributing factors resulting in the incident.
5-Whys
Developed in the 1970’s for Toyota Industries Corporation by Sakichi Toyoda, this technique aims to find the root cause of an incident by asking what happened and continually asking “why?” that happened until the root cause is found. It is named 5-Whys as it has been found that asking “why?” five times is sufficient to get to the root cause. The benefits are that the technique is easily learned and applied, however an experienced investigation team is required, with outcomes not always repeatable i.e. different teams may determine different root causes for the same incident.
Again this is not a complete investigation method. It is a data organisation tool often used as the next step of ICAM.
ICAM (Incident Cause Analysis Method)
ICAM sets a framework for investigating safety incidents based on organisational, environmental and human factors to establish the failures. ICAM is a holistic approach which goes beyond the obvious or superficial reasons for an incident. It aims to identify the underlying factors that may have contributed to the incident and to the context in which they occurred and takes into account any weaknesses that might be lying dormant with the organisation itself.
ICAM includes the PEEPO and 5-Why’s techniques as steps in a more comprehensive investigative method typically used for more serious or complex incidents.
ICAM incorporates the following steps:
Determine what happened – Use of PEEPO
Determine why it happened
Determine what you are going to do about it – Using the hierarchy of controls
Determine key learnings that may be shared
A full ICAM can be seen as cumbersome and requires significant input and detail to be effective.
The team at MicroRisk Group are trained in ICAM and have significant experience in the investigation of incidents both in the private sector and as the health and safety regulator. MicroRisk Group can assist you by undertaking an independent incident investigation, review an investigation you’ve undertaken internally or review your investigation procedure. See our Services for more information.