Abstract: A classification tree generating system generates a classification tree in response to a training database including a plurality of properly-classified records. A parallel base tree generating means including a plurality of processing nodes generates nodes of a base classification tree in parallel in a series of iterations, in each iteration generating nodes comprising a particular tree level in parallel. After the processing nodes generate the base classification tree in parallel, a serial tree processing means including a single processor generates a plurality of pruned classification trees in response to the base classification tree and at least one selected evaluation metric for each of the pruned trees in response to an evaluation training database including a second plurality of properly-classified records.