If the goal of a speech is to persuade, what is the best indicator of success?

The best indicator of success for a persuasive speech is the listeners' actions after the speech. This outcome directly reflects whether the audience has been convinced to adopt a new viewpoint, take a specific action, or change their behavior in line with the speaker's message. If the audience acts on the information or arguments presented in the speech, it demonstrates that persuasion was effective.

While audience engagement and listeners’ feedback can provide valuable insights during the speech, they do not necessarily confirm that the listeners have internalized and acted upon the persuasive message. Similarly, speaker confidence is important for delivering a compelling speech, but it does not measure the actual change in audience behavior or belief. Ultimately, the actions taken by the audience serve as the most concrete evidence of successful persuasion.