Event Tree Analysis, ETA
Feb 26th, 2015
In this blogpost we look at another tool: the Event Tree Analysis, ETA.
Event Tree Analysis, ETA
In our day to day practice we frequently see risk assessments methodologies stretched to «fit the clients’ case». In other words, people select tools to deliver results out of the initial methodology’s scope. This blogpost is a brief summary for the Event Tree analysis (ETA). It is one of the most common methodologies to evaluate probabilities of complex cascading events in terms of series of conditional probabilities.
In reality, Event Tree Analysis, ETA, is a graphic-mathematical forward, bottom-up, logical modelling technique. It is a common mistake to develop excessively complex ETA giving their users a false sense of security and precision.

Event Tree analysis, (ETA). Example of a tailings dam failure.
Event Tree Analysis, ETA, start with a single initiating event and develop with cascading branches and nodes.
You can use ETA to:
- Evaluate success and failure probabilities of cascading events, as well as to
- analyze the failure paths leading to different classes of events
In fact, ETA is a failure analysis tool. As such, you can integrate it in Quantitative Risk Assessments.
Tagged with: complex cascading events, conditional probabilities, failure analysis tool, methodology
Category: Probabilities, Risk analysis
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