Many scientific, business, and government documents and presentations are written to explain or to share information. A product roll-out, a literary analysis, even an agenda or event schedule may employ this purpose. So might a presentation that introduces new initiatives or explores solutions to particular issues. When the subject matter is the focus, explanation is the purpose.

An explanation can be developed in several ways—through comparing and contrasting, through showing causes and effects, by defining elements or processes, by giving examples. It can follow a chronology or divide components into specific categories that are then examined.

The purpose of some communication, both oral and written, is to express feelings or to share emotions; in this type, the focus is the speaker or writer. A position statement, a keynote address, a response to a client or colleague may aim to articulate feelings and define sentiments as varied as commitment and indifference, gloom and glee, or the waxing and waning of hope.

The structure of an expressive piece depends heavily upon narration and description, using both to exemplify the emotions that are core messages. It may be organized as a discovery, exploration, or journey; it may present facts, conditions, or events from which emotions evolved.

At times, writers and speakers intend to entertain and amuse; they focus on language to help them achieve that aim. Through stories and wit, through diction and figures of speech, through style and delivery, they weave a cloth that wraps the audience in joy or reflection, passion or thought. As a purpose, entertainment is not necessarily light; it can be very serious. A commencement address, an after-dinner speech, or a kickoff meeting may be so absorbing that entertainment is its primary objective.

Organizing an expressive piece as an upward trajectory creates the condition for such absorption. Build tension by introducing conflict; select anecdotes or stories that illustrate or reflect that conflict. Connect thoughts to emotions and past to present. Weave your cloth.

Persuasion becomes your purpose when you want readers or listeners to do something—to change their stance on an issue, to approve a new policy or product, to consider a particular perspective or solution. You focus, then, on them, on how to make your message acceptable to them. You develop your message with reasoning and evidence that is convincing to them although the next audience you address may require something different. Both inductive and deductive patterns can provide an effective framework.

And especially when your purpose is to persuade, you carefully balance credibility, logic, and emotion to complement audience characteristics (see ethos, logos, and pathos).

Recognizing your purpose in a document or presentation leads you to appropriate choices regarding content, organization, and support. It guides you toward an effective tone and style. It helps you discover and articulate messages by telling you where to look—at subject matter, yourself, language, or audience. Determine the why and then build a path of what towards it. You'll achieve it. Our client did.