Event Factor Chains Charting and Explanation

Events are occurrences that take place in order for a task to be completed. In the case of causal factor analysis, events describe a single occurrence, and are short, to the point, and contain detail. The level of detail depends on the task that is performed. For example, The plane descended 200 feet, not The plane lost altitude and the pilot went by proper procedures to regain altitude. It is up to you, as the investigator, to establish that level of detail. 

Events should be used in a causal factor analysis only if they pertain to the accident. If the event is not pertinent to the accident, exclude it from the analysis. For example, do not include The worker called her husband on her lunch break. However, do include The worker lifted the 100-pound block over her head, which led to her hurting her back.  

Any as-found or existing state that influences the outcome of a particular task, process, or operation 

FIGU RE 9.2 Causal factor relationships. (Source Courtesy of the United States Department 

Conditions are the states or circumstances surrounding the accident, rather than the happenings. They are inactive elements that increase the possibility for the accident to occur. An example of this would be The ground is wet. Just like events, when possible conditions should be described, quantified, and posted with time and date. Always record the conditions immediately preceding the event. An example of this would be that the worker did not know how to stop the backhoe from rolling down the hill, and the worker lost control of the backhoe. 

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