Computerized method and system for making decisions based on evidential reasoning are provided. The method allows for providing a model structure; including a plurality of processing nodes. Each of the processing nodes is coupled to receive a set of inputs to supply a respective output. The method further allows for evaluating a respective attribute assigned to each of the plurality of processing nodes. A number of possible linguistic evidential values is specified for each of the attributes, wherein some of the evidential values comprise unknown information. A combining step allows for combining the outputs from the processing nodes to reach a decision even in the presence of unknown information.