The Sequential OR (SOR) node selects the first path of adequate quality where adequate quality is determined by sufficiency of data.
The SOR node is used to pick among competing evaluation methods where the methods are arranged in descending order of preference. Often the first choice method of determingn some property is not available but another, less desireable method is available. The SOR node provides a way of switching between these competing methods based on how well each method is currently functioning based on the sufficiency of the data driving the method.
This quality of the path is determined by the magnitude of the child-node's data satisifaction compared to the child-node's weight1).