The sequence structures we have been describing are the outcome of practices of sequence construction. They are the product of a convergence between practices for implementing a course of action-in-interaction through talking, and the structures of talking through which such a course of action can be implemented. The fact that there are robust, recurrent forms and structures of sequences which are precipitated out by these practices testifies to the recurrence of certain interactional and sequential contingencies which press for solution and resolution, and which, given the way in which talk-in-interaction is otherwise organized (its turn-taking and turn-constructing practices, the availability of the resources and practices of repair and the structuring they appear to have, etc.), recurrently get resolved in ways embodied by these sequence structures. They document interactants' recurrent solutions to exigencies of interaction, of talking-in-interaction, and of building courses of action.

Still, these structures are not rigid prescriptions. Who would have prescribed them? Who would enforce them? If they are the precipitate of recurrently employed practices, we must expect that there will be occasions on which interactional and sequential contingencies occasion or invite the use of different practices, or different uses of the same practices, yielding organizational or structural outcomes that vary from the most commonly observed ones. These provide opportunities to sort out what in our observations displays the underlying driving contingencies and their solutions, and what is better understood as the common, but not deeply rooted, surface manifestation or realization of the practices-as-responses-to-contingencies.