Martin (1992: 456):
Public speakers (and even writers, at a time when composition was taught in schools) are commonly advised: "tell your audience what you're going to say, say it, and then remind them what you've said". The generally cited Introduction ^ Body ^ Conclusion formula for expository texts makes the same point (as does Orientation ^ Complication/Resolution ^ Coda for narrative). What this wise counsel represents is the tendency for whole texts in English to symbolise the Theme ^ Rheme and Given ^ New structure of the English clause.
 As this demonstrates, the field here is writing pedagogy, not linguistic theory.
 What these three schemas actually have in common is that they are ways of naming the time-phases (inception, duration and termination) of a process — in this case, the unfolding of text (logogenesis). This is quite distinct from Theme and New, which highlight the textual status of experiential and interpersonal content.
 Given ^ New is not a structure of the English clause. They are functional elements of the information unit.