Causation models

The system-induced error approach can be restated in an alternative form as an accident causation model (see Figure 1.4). This shows how error-inducing conditions in the form of inadequate PIFs interact with error tendencies to... 

FIGURE 6.2. Accident Causation Model (From Chapter 2). 

Because of the emphasis on modeling accident causation, data collection systems based on the system-induced error approach are likely to modify their data collection strategies over time. Thus, as evidence accumulates that the existing causal categories are inadequate to accoimt for the accidents and near misses that are reported, the data collection philosophy will be modified, and a new accident causation model developed. This, in turn, will be modified on the basis of subsequent evidence. 

In this section, a real case is presented so that the accident causation model can be applied to identify the root cause of the errors (BBC News, 1999a-g). 

When we apply the accident causation model, the following key root causes will be identified. 

Chua, D.K.H. and Goh, Y.M. (2004) Utilising the modified loss causation model for the codification and analysis of accident data. In S. Rowlinson (ed.). Construction Safety Management Systems, pp. 443-63. Spon Press, London. 

The STAMP (Systems-Theoretic Accident Model and Process) model of accident causation is built on these three basic concepts—safety constraints, a hierarchical safety control structure, and process models—along with basic systems theory concepts. All the pieces for a new causation model have been presented. It is now simply a matter of putting them together. 

OBSERVATIONS ON CAUSATION MODELS FOR HAZARDS-RELATED INCIDENTS 3... 

If several safety professionals investigate a given hazards-related incident, they should identify the same causal factors, with minimum variation. That is unlikely if the thought processes they use have greatly different foundations. At least 25 causation models have been published. Since many of them conflict, all of them cannot be valid. A review of some of them is followed by a discussion of principles that should be contained in a causation model. 

A SYSTEMIC CAUSATION MODEL FOR HAZARDS-RELATED INCIDENTS... 

In the causation model presented in this chapter, there is a plea for recognition of the impact an organization s culture has on causal factor development, as well as for a balanced, systemic approach that addresses the design and engineering, the management and operational, and the task performance causal factors. 

The emphasis given in his accident causation model, called the accident sequence, to the faults of persons and to ancestry and environment, which identified the traits of individuals as the principal causative elements (Citation 7)... 

This chapter addresses the need for safety professionals to adopt an incident causation model, a thought process based on a sound understanding of the hazards-related incident phenomenon and which, when applied, identifies the reality of the causal factors in the incident process. 

PROFESSIONAL SAFETY PRACTICE REQUIRES ESTABLISHING AN ACCEPTED CAUSATION MODEL... 

Dr. Roger L. Brauer, Executive Director of the Board of Certified Safety Professionals, made the following comment about proving the validity of causation models ... 

Safety professionals apply differing and contradictory incident causation models, and the work of some of them is misdirected and ineffective. Professional safety practice requires that the advice given to avoid, eliminate, or control hazards be based on a sound incident causation model, a thought process, so that, through the application of that model, the desired risk reduction is attained. That will not occur if the causation model used does not require identifying the actual causal factors. 

If we who call ourselves safety professionals are to be tmly perceived as professionals, we must resolve this matter of a generally accepted hazards-related incident causation model. A major study on this subject would be to our advantage. 

INCIDENT CAUSATION MODELS REPRESENT GREAT DIVERSITY OF THINKING... 

Benner rated only the models and investigation systems used in 17 selected government agencies. At least 25 causation models are referenced in safety literature. They present a great diversity of thinking. 

The following quotation from a letter received from Bernier gives one indication of the divergence of thinking about accident and causation models ... 

Accident models and accident causation models involve two different areas of endeavor. The point is subtle, but in my view it is absolutely imperative to recognize the difference. Causation models purport to present cause and effects without identifying the phenomenon no beginning and end of the phenomenon is indicated. Accident models on the other hand, deal descriptively with accidents as a process that has a beginning and an end, and the elements of that process. Please help me keep my models in the latter arena when quoting any of my work to ensure that it is not thrown into the causation model arena inadvertently. 

Several authors have recognized, with some fmstration, the absence of and a serious need for a generally accepted accident causation model. Robert E. McClay addressed the subject in his paper titled Toward a More Universal Model of Loss Incident Causation ... 

One of the difficulties to be overcome in establishing a causation model is determining what is to be encompassed and what terms are to be used in the description. This is from McClay ... 

Safety professionals give many names to the incidents to which a causation model would apply accidents, incidents, mishaps, near-misses, occurrences, events, illnesses, fires, explosions, windstorms, drownings, electrocutions, and so on. Pat Clemens, a prominent safety consultant, has said that the language used by safety practitioners lacks words to convey precise and understood meanings. It s probable that the people with whom safety professionals try to eommunicate are baffled by the many terms used to describe hazards-related incidents. 

A practice of safety based principally on the many extensions of the causation model represented by the domino sequence developed by H. W. Heinrich that focus on the so-called unsafe act or human error as the principal causal factor will be ineffective in relation to the actuality of causal factors. 

A sound causation model for hazards-related incidents must identify and stress the significance of the design management aspects and the operations management aspects and the task performance aspects... 

CONCERNING CAUSATION MODELS BASED ON HEINRICHEAN PRINCIPLES... 

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