7. An apparatus according to claim 6 wherein the structured electronic representation of the document comprises a plurality of tags identifying respective fields including the at least one symptom and the plurality of the components that are causally related to the at least one symptom, and wherein said processor automatically identifies the at least one symptom and the plurality of components that are causally related to the at least one symptom based, at least in part, upon the plurality of tags.
6. An apparatus for constructing a diagnostic network model comprising: a processor for automatically reviewing a structured electronic representation of each of a plurality of different types of documents including automatically identifying at least one symptom, a plurality of components and causal relationships between a failure of respective components and occurrence of the at least one symptom by mapping the failure of a respective component to at least one symptom to establish a respective causal relationship, wherein said processor also associates respective probabilities with the causal relationships between the at least one symptom and the plurality of components whose failure contributes to the at least one symptom, wherein the processor is configured to obtain respective probabilities from an individual participating in construction of the network model by eliciting the probability associated with the causal relationship between at least one symptom and the failure of a respective component and receiving input from the individual of the elicited probability, wherein said processor automatically constructs the network model of the at least one symptom, the plurality of components, the causal relationships therebetween and the probabilities of the respective causal relationships, and wherein the processor is configured to display a representation of at least a portion of the network model.