1. A method for constructing a diagnostic network model comprising: automatically reviewing a structured electronic representation of a document, wherein automatically reviewing comprises automatically identifying at least one symptom, a plurality of components and causal relationships between a failure of the respective components and the occurrence of at least one symptom; associating respective probabilities with the causal relationships between the at least one symptom and the plurality of components; and automatically constructing 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.