1. A computerized method for making decisions based on evidential reasoning, said method comprising: providing a model structure including a plurality of processing nodes, each of said processing nodes coupled to receive a set of inputs to supply a respective output; evaluating a respective attribute assigned to each of the plurality of processing nodes; specifying a number of possible linguistic evidential values for each of said attributes, wherein some of said evidential values comprise unknown information; and combining the outputs from said processing nodes to reach a decision even in the presence of said unknown information, said combining configured to emulate expert data.