It would seem obvious. Before preparing your live pitch you must decide what it is you want say. Too often pre-pitch proposal documents, running to a hundred or more pages, are simply squeezed and condensed  into a 30 minute time slot, holding onto as many selling facts as possible.

Saying everything runs the risk of communicating nothing.

You cannot compose a persuasive pitch or presentation until you have first worked out your cental message, the core proposition. This is as true for a pitch as it is for a speech or a campaign. In its creative heyday, Saatchi & Saatchi held to a rigorously observed principle that creative work  could only be developed from:

A singleminded proposition brought alive in a compelling way.

 Unlike Mad Men, where campaigns emerge over a cigarette and a whisky,  more time might be spent arriving at the right proposition  than on the campaign messages. The forensic Creative Director rejected out of hand woolly propositions.

Graham Davies in  his excellent book, The Presentation Coach–Bare Knuckle Brilliance For Every Presenter, describes the proposition as the Micro-Statement. “It is the foundation on which your content will be built. Everything that you eventually say in front of the audience should be calculated to convince them to accept and act on the Micro-Statement”

The book is worth reading.