Abstract--With the availability of large corpora of spoken dialog, it is now possible to use data-driven techniques to build and use models of task-oriented dialogs. In this paper, we use datadriven techniques to build task structures for individual dialogs, and use the dialog task structures for: dialog act classification, task/ subtask classification, task/subtask prediction, and dialog act prediction. We evaluate our approach using a corpus of customer/ agent dialogs from a catalog service domain. This paper demonstrates the feasibility of using corpora of human