Executive Communication 5 types of evidence essential for persuasive speeches Rob Friedman, Eli Lilly’s senior director of communications, says your evidence must be relevant, grab people’s attention, and resonate emotionally. By Matt WilsonApril 10, 2012 SHARE To read the full story, log in. Become a Ragan Insider member to read this article and all other archived content. Sign up today Already a member? Log in here. Learn more about Ragan Insider.