14. A method comprising: accessing, with a processor, at least a portion of a diagnostic network model that associates a plurality of components and symptoms based upon causal relationships therebetween, wherein the causal relationships associate a failure of respective components and occurrence of the at least one symptom; associating, with the processor, a probability with the causal relationship between a symptom and a respective component whose failure contributes to the symptom, wherein associating a probability comprises providing the probability which was obtained from an individual participating in construction of the diagnostic network model; displaying, with the processor, a representation of the plurality of components and symptoms including a plurality of parent nodes representative of the components, a plurality of child nodes representative of the symptoms and a plurality of influence arcs extending between respective parent and child nodes and associated with respective probabilities; receiving a selection, with the processor, of at least one of the plurality of components and symptoms from among the plurality of components and symptoms that are displayed; and in response to the selection and with the processor, obtaining and displaying additional information related to the at least one of the components and symptoms that is selected.
20. A method according to claim 14 further comprising displaying each component whose failure is capable of causing the at least one symptom that is selected.