The Use Of Evidence In Your Presentations

We flagged this point last episode, and today we’re getting practical about evidence in presentations.
We now live in the “Age of Distraction” (people escape to the internet, even while they’re interested) and the “Era of Cynicism” (audiences are more sensitive to whether information is valid).
If we fill our presentations with opinion, we lose them. If we bring concrete insights backed by proof, we keep them.

Dr. Greg Story, Ph.D. in Japanese Decision-Making, is President of Dale Carnegie Tokyo Training and Adjunct Professor at Griffith University.
He is a two-time winner of the Dale Carnegie “One Carnegie Award” (2018, 2021) and recipient of the Griffith University Business School Outstanding Alumnus Award (2012).
As a Dale Carnegie Master Trainer, Greg is certified to deliver globally across leadership, communication, sales, and presentation programs.

Why is evidence more important now than ever?

Because “editorial” and opinion won’t hold attention in the Age of Distraction—and they won’t survive the Era of Cynicism. Even when people are interested, many are still multitasking: listening while scrolling social media, which makes it harder for your message to land. When the content is mostly “my view,” the audience often doesn’t feel enough value to keep paying attention. Evidence changes the trade: you’re not asking for belief, you’re supplying proof. In practical terms, that means fewer “trust me” statements and more “here’s what we can verify” statements, so your talk feels credible whether you’re speaking to an SME audience, a multinational, or a government group.

Do now: Highlight anything in your talk that is pure opinion and ask, “Where’s the proof?”

What makes evidence credible in the Era of Cynicism?

Credible evidence is highly trustworthy, uses multiple sources, and is transparent about how the findings were assembled. Fake news has made audiences more suspicious, so “because I said so” doesn’t travel far anymore. Using numerous sources helps, because it signals you didn’t cherry-pick one convenient statistic. And if you quote your own research, it can work well—but you need to explain how you did it (how you gathered it, over what timeframe, and what you looked at), otherwise it may be greeted with doubt. This is especially important in senior rooms where people are trained to challenge assumptions and test validity.

Do now: If you cite your own research, add one plain-English line explaining the method and how the findings were assembled.

What are the best types of evidence to use in a presentation?

Use the DEFEATS framework to match each key point with the right type of proof.
DEFEATS is a handy acronym for remembering the different evidence options available when you want to convince (or impress) the audience that what you’re saying is true.
The big idea is simple: don’t just “say the point” and move on. When you hit each key point, attach evidence deliberately so the audience can track your reasoning and feel confident you’re not winging it.
This also helps across cultures and industries: a technical audience may prefer demonstrations and data sources, while a people-focused audience may respond faster to examples, analogies, and testimonials.

Do now: For every key point, choose at least one DEFEATS proof type (and two if the audience is sceptical).

What does DEFEATS mean (and how do you use each type well)?

Each DEFEATS element does a different job—so match the evidence type to what you’re trying to prove. Here’s how the framework breaks down:

• D — Demonstration: show something physically or on-screen (software, audio, video) that visually reinforces the point and stays congruent with your message.

• E — Example: choose examples that will resonate with the audience (same industry, similar organisation size) so it feels relevant.

• F — Facts: facts must be provable and independently verifiable; show the source prominently on graphs.

• E — Exhibits: show a physical item (or image) clearly—shoulder height, not waving around.

• A — Analogies: connect unrelated concepts to simplify complexity (e.g., aircraft take-off/landing vs speech opening/closing).

• T — Testimonials: social proof isn’t the main evidence, but it boosts credibility—especially from recognised experts.

• S — Statistics: third-party stats are strongest; your own are fine but less convincing without independent numbers too.

Do now: Add the data source to every chart and “fact slide.” Most people won’t check—but they feel better knowing they can.

What evidence mistakes make audiences switch off?

The biggest mistakes are using examples the audience can’t relate to, and presenting “facts” without checkable sources.
A classic mismatch is a senior executive from a major organisation speaking to a room full of small-to-medium companies using only big-company examples—there’s nothing to relate to, so the proof doesn’t land.
Another credibility leak is showing graphs or “facts” without displaying where the data came from. You may be accurate, but the audience can’t tell—and in a cynical environment, that doubt spreads quickly.
Make your evidence feel relevant (their world) and verifiable (checkable), and you’ll hold trust longer—especially with time-poor executives and analytical stakeholders.

Do now: Ask, “Is this example their world?” If not, swap it. Then make every key number traceable to a named source.

Conclusion

Evidence is what keeps a distracted, cynical audience with you right through to the end. Build your argument, identify your key points, then deliberately match each point with hard proof using DEFEATS—demonstrations, examples, facts with sources, exhibits, analogies, testimonials, and statistics.
If you do that, you’ll have a much better chance of holding attention all the way to your close—even when the internet is one click away.

Next steps for leaders/executives:
• Replace “opinion” lines with at least one DEFEATS proof type.

• Put sources on charts so facts feel checkable, not asserted.

• Use examples matched to the audience’s industry and company size.

Author Credentials

Dr. Greg Story, Ph.D. in Japanese Decision-Making, is President of Dale Carnegie Tokyo Training and Adjunct Professor at Griffith University.
He is a two-time winner of the Dale Carnegie “One Carnegie Award” (2018, 2021) and recipient of the Griffith University Business School Outstanding Alumnus Award (2012).
As a Dale Carnegie Master Trainer, Greg is certified to deliver globally across all leadership, communication, sales, and presentation programs, including Leadership Training for Results.
He has written several books, including three best-sellers — Japan Business Mastery, Japan Sales Mastery, and Japan Presentations Mastery — along with Japan Leadership Mastery and How to Stop Wasting Money on Training.
His works have been translated into Japanese, including Za Eigyō (ザ営業), Purezen no Tatsujin (プレゼンの達人), Torēningu de Okane o Muda ni Suru no wa Yamemashō (トレーニングでお金を無駄にするのはやめましょう), and Gendaiban “Hito o Ugokasu” Rīdā (現代版「人を動かす」リーダー).