Accident Investigation Models

Personal damage occurrence (Accident) Investigation Models

Guest Post by George Robotham


Personal damage occurrences (“Accidents”) may be a source of learning and improvement for the safety management system if they are well investigated and appropriate corrective action implemented. The term accident is an emotionally laden term that infers blame, the term should be avoided. The common wisdom when developing controls is to apply the hierarchy of controls, I believe applying Haddon’s 10 countermeasures will give a better result.

Why do we investigate?

Statutory requirement-Various safety legislation requires specified events is to be investigated

Corporate policy-Various company policy requires investigations

Aid to common law actions-Common law determinations require detailed evidence

Io maintain employee relations-The majority of employers will say our people are our greatest assets and investigation is part of caring for employees

Most importantly-Change for the future, not BLAME for the past

Personal experience with investigation

I have read about or been trained in a number of personal damage occurrence (Accident) investigation models, included in these have been Tap Root, Tripod, I.C.A.M., Root Cause Analysis and A.R.T.T.

The method I strongly favour is the Geoff McDonald developed A.R.T.T. (Analysis Reference Tree Trunk) A.R.T.T. is the only model I have seen that makes a very strong distinction between identifying essential factors and looking for someone to blame. I also find you get to understand the event better with A.R.T.T. than with the other models.

I have used this technique for ages and believe it produces very high quality investigations. I have been trained in a few other investigation methods and have read widely on the topic, I still keep coming back to A.R.T.T. For a number of years I used to teach a 2 day course on this method and some excellent investigations resulted. The course also allowed people to challenge the more common beliefs about safety.


There are 2 mental shifts required to use A.R.T.T.

Mental shift 1

Look for essential factors not causes. An essential factor is one without which the final damage would not have occurred. Cause is an emotionally laded term that infers blame and it should not be used.

Mental shift 2

Essentially the personal damage occurrence is represented by a tree-trunk lying on the ground, at the end of the tree-trunk you have Person elements, Machine elements and Environment elements, along the length of the tree-trunk you have 6 time zones and the annular or growths rings of the tree represent a number of Ergonomic elements. Instead of looking for “causes” you look for “essential factors” ( an essential factor is one without which the final personal damage could not have occurred) The idea is to look for essential factors where the various categories of the model above intersect.

There is a worksheet that incorporates the foregoing that guides your thinking in identifying essential factors.

The model is very easy to use and usually at least 30 essential factors will be found in each personal damage occurrence. This widens your options for control over some other methods of personal damage occurrence investigation.

Brisbane-based OHS consultants, Intersafe conduct reportedly excellent courses on the essential factors methodology and A.R.T.T. Look up their web site and give Roger Kahler a ring.

Ted Ferry out of America has 2 books on accident investigation that I thought covered the nuts and bolts of the topic pretty well.

Please note that I have no commercial relationship with Geoff McDonald or Intersafe, the reason I strongly recommend A.R.T.T. is that I have used it for many years and believe it represents best practice.

You may be interested in my accident investigation paper that is available on request.

George can be contacted on, he welcomes debate on the above (it would be indeed a boring world if everybody agreed with George)

George Robotham, Cert. IV T.A.E.,. Dip. Training & Assessment Systems, Diploma in Frontline Management, Bachelor of Education (Adult & Workplace Education), (Queensland University of Technology), Graduate Certificate in Management of Organisational Change, (Charles Sturt University), Graduate Diploma of Occupational Hazard Management), (Ballarat University), Accredited Workplace Health & Safety Officer (Queensland),Justice of the Peace (Queensland), Australian Defence Medal, Brisbane, Australia,,,07-38021516, 0421860574, My passion is the reduction of permanently life altering (Class 1 ) personal damage

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