What is an Event Tree?

An event tree is part of certain analytical methodologies. It is essentially a concept, often drawn out as a diagram, that shows a chain of cause-and-effect for a range of events. An event tree graph or model can be effective in displaying the probability of results or conditions for a complex procedure.

An event tree is often said to use "Boolean" values. A Boolean value is a dialectical representation such as "true or false" where one of two conditions is displayed. Boolean values often come into play, where an event or condition is either true or false for a specific portion of the diagram.

In an event tree, there is generally one root event, usually a problem, drawn at the top or beginning side of the diagram. That event splits into possible results. Each result is its own event, with other results stemming from it. The end result is that the tree branches out until the various final results are displayed at the bottom or end of the tree.

As a simple example, an event tree could be drawn with the root event being a fire in a building. The first step in the tree might be to ask whether or not the fire is detected. If the answer is "no," the result is that the building is destroyed. An answer of "yes," however, leads to the next question in the tree, whether or not the sprinkler system worked. Each step in the tree leads to a binary question, with only one branch outlining a sequence in which all steps are successful.

Some event trees include the probabilities for each of their branch results. With probabilities included, engineers can do a large amount of predictive troubleshooting that can help avoid or fix problems. By the same basic process, a computer can also effectively model a situation, and point out the most likely causes of an outcome.

An event tree may be part of a software package or other analytical tool in many different fields. The top uses for event trees are in scientific fields like laboratory analysis for pharmaceutical or other testing. They can also be helpful in fields like retail or manufacturing, where logistics or market research could benefit from this kind of analysis. Another use for event trees is in product oriented research. For example, in the motor vehicle industry, an event tree could be helpful in showing or even predicting specific types of vehicle breakdowns.

Another distinguishing feature of different event trees is in their respective formats. They can be drawn out on paper for distribution at a presentation. Web-based event trees can also be useful for presentations, but often, they are worked into an algorithmic interface, or other software design, for analytical or predictive modeling.