Event tree analysis pathway

Eault tree analysis is used to assess the frequeney of an ineident. A fault tree is a diagram that shows how primary eauses produee events, whieh ean eontribute to a partieular hazard. There are several pathways in whieh a single primary eause ean eombine with other primary eauses or events. Therefore, a single eause may be found in more than one hazard and may oeeur at different loeations in the fault tree. 

With tree analysis it is possible to infer sequences of ancestral proteins and probable evolutionary pathways to their modern descendants.1 The advent of site-directed mutagenesis makes possible the recreation of evolutionary intermediates based on these predictions. One may then compare the properties of reconstructed intermediates with one another and with proteins from contemporary creatures. These comparisons provide a way of testing theories about the mechanism of molecular evolution. For example, this approach has provided a new criterion for distinguishing between neutral and nonneutral events.2 This chapter describes the use of site-directed mutagenesis to recreate ancestral lysozymes and presents methods of evaluating their properties. 

A Fault Tree Analysis (FTA) is a top-down, deductive logic model that traces the failure pathways for a predetermined, undesirable condition or event, called the TOP Event. An FTA can be carried out either quantitatively or subjectively. The FTA generates a fault tree (a symbolic logic model) entering failure probabilities for the combinations of equipment failures and human errors that can result in the accident. Each immediate causal factor is examined to determine its subordinate causal factors until the root causal factors are identified. 

Cost identification often involves the development of a probability or decision tree of the therapeutic pathway that describes all relevant downstream events related to use of that therapy and its comparator(s). Once the relevant resources are identified and measured (e.g. number of physician visits, treatment of side effects, number and duration of hospital visits, etc.), local costs/prices can be applied to those resources to determine the overall cost of that intervention. The scope of the resources (and costs) included in an analysis is determined by the perspective (or intended audience) of the study. 

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