Incident decision tree

The structure of the NPSAs Incident Decision Tree is shown in Figure 14.1. Essentially, after the incident has been investigated and some thought given to its causes, a series of questions is asked. Were the actions intentional If, yes, was there an intention to cause harm or not Is there any evidence of a medical condition Was there a departure from agreed protocols and so on. Suppose, for instance, a staff nurse gives a dose of diamorphine to an elderly patient in severe pain without waiting for a prescription to be written. Is this justified Potentially, if there is no other option. Suppose, however, she has made no attempt to contact the relevant doctor. In this case her actions were clearly intentional. 

Figure 14.1 Incident Decision Tree adapted from UK National Patient Safety Agency.

Using the incident decision tree requires an initial analysis of the case and some reflection on the web of causes and contributory factors and the intentions and... 

Module 4 (Classification) to aid every employee in understanding and applying the RAP classification scheme, a simple form of decision support has been developed and fully integrated within the database interface. It consists of a series of yes/no questions which follow exactly the decision tree (adjusted to the RAP model) of figure 5.2. Each question is illustrated by two examples one based on a true incident (or an element thereof) from the RAP safety files, which should be very recognisable and valid for every operator the other based on an aspect from a task environment familiar to both RAP operators and almost everyone else car driving. 

The next item in the loop is a decision point for possibly introducing the use of inductive reasoning methods into the deliberations. If the deductive process continues to indicate progress, then additional facts are procured or the logic tree is restructured. For example, one witness stated a particular valve was open, yet the post-incident inspection found it to be closed. The team must be careful to ensure that the valve is closed because of the actions taken prior to the incident, and not as a result of post-event response activities. The position of this particular valve may be a critical item in determining which of two scenarios is the more probable case. The incident investigation team would then initiate a short-term action item to conduct a mini-investigation to resolve this question. 

Safety analysis uses logic structure representative of possible incidents. Such work methods as fault tree, incident analysis, and decision table are suitable for this purpose. Computation rules for determination of expected frequency of incidents must be formulated accordingly. In a broad sense all mathematical simulation methods which are suited for determination of stress states in technical installations and their parts become aids in safety analysis. These will be described in partial detail later. Here characteristic work methods which are of direct significance with respect to system-related and prognostic consideration of safety analysis will be discussed first,... 

System behavior analysis and prognosis can be executed by means of various procedures. The procedures generally described in the literature can be traced back to three standard types, namely failure effect analysis [4-9], fault tree analysis [4-10], and incident progression analysis [4-11], The three procedures will be discussed, as well as the concept of the decision table technique, which is also a good tool but has rarely been discussed in the literature in connection with this application. To begin, the customary analysis techniques [4-9], [4-10], [4-11] will be discussed in alphabetical order. This will serve to delineate and distinguish the procedures. 

Decision Table Technique. Fault tree analysis and incident sequence analysis are methods leading to the representation of the logic structure of... 

When undesired incidents which can bring about failures are investigated in this manner, then, by means of fault tree analysis or the decision table technique, system behavior in the case of such incidents can be examined. If the required data are available, weak-point analysis can be continued quantitatively. 

System Structure Analysis. After the identification of subsystems to be examined and the definition of undcsired events within the context of preliminary hazard analysis, events which lead to incidents are investigated. These event sequences can be represented as logic structure in a block diagram, a flow diagram, a fault tree, or a decision table. In the presentation which follows (Table 4.9.). a decision table was used. It contains, column by column, the combinations of system states which lead to the undesired event. The presentation permits qualitative identification of weak points in the system. In general, for example, the probability of a system state will decline with the growing number of failed components. The logic structure presentation could form the basis for further quantitative analyses. 

Event trees are mainly associated with accidental incidents. They ate applied to both pre- and post-accidental incidences. In case of pte-accidents, they tty to predict the outcomes and helps to design barrier systems. For post-accidental incidents, they help to find the range of likelihood and potential outcomes. From the above discussions it is clear that ETA helps for decision-making on ... 

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