To present is to persuade a little—or, sometimes, a lot.

No matter the topic or occasion, a speaker generally wants to move the audience to understand a position, to accept a belief, to take an action, or to feel a specific emotion. By some measure and to varying degrees, the speaker's goal is to persuade.

Achieving an outcome through persuasion depends heavily on the speaker's credibility, or ethos. According to the ancient Greek philosopher Aristotle, ethos is "the controlling factor in persuasion." Thus while the other two factors he names (reason and emotion) matter greatly, it is the credibility or ethos of the speaker that sets the stage for persuasion and its success.


Listeners assess the character of the speaker to form an opinion on how believable he is. When they perceive that he possesses sufficient "wisdom, virtue, and good will," they tend to believe what the speaker says. But if they find him lacking in any of these areas, they lose trust. A speaker who cannot inspire trust lacks credibility.

An audience expects the speaker to be a person who can demonstrate his intelligence and knowledge, honesty and integrity, understanding and compassion. Yet members of an audience may hold differing views on what constitutes each of these qualities. Undertaking an audience analysis as a part of planning a presentation helps a speaker shape ideas, organize content, select language, and provide support to meet the standards by which a particular audience judges credibility.


At times, a speaker's reputation, expertise, or experience alone can create ethos. An audience is predisposed to find such a speaker credible, to find him trustworthy, and so to find him persuasive. During an FDA Advisory Committee Meeting, for example, comment from persons who experience a particular condition or disease may create ethos as readily as reports from highly regarded researchers and practicing physicians.

As a speaker, you can weave your experience and expertise into your presentation. Consolidate your authority through storytelling, narrating events that introduce or illustrate your messages. Use the language or vocabulary of your audience to show that you are aware of their background and respectful of their position within their discipline or learning community. Use quotations, references, and citations from the experts and publications your audience considers most prominent.

Craft examples that connect with your audience and prove meaningful to them.


Adopt a tone that communicates respect for both your subject and your audience, one that is even-handed, fair, rational. While your delivery may change, becoming at times impassioned or solemn or even humorous, your tone should be consistent. Its level of formality should also be sustained and based upon the occasion as well as on your connection to the audience. Take care to acknowledge different points of view to demonstrate both your knowledge of the subject and your understanding of your audience.

And, as always, use your physical presence to strengthen your credibility.

In a presentation, you are never not persuading. Develop your ethos well, because, as the very creditable Aristotle believed, it "may almost be called the most effective means of persuasion [one] possesses."