Methods and apparatus for classifying data for use in data fusion processes are disclosed. An example method of classifying data identifies classification tree information and assigns values to each of a plurality of nodes associated with the classification tree information. Each of the values is indicative of a relationship between its respective node and one of a plurality of classes. The example method also assigns each node to one of the classes based on a comparison of at least two of the assigned values and classifies the data based on the assignment of the nodes to the classes.