The Use Of Evidence In Your Presentations

We flagged this last episode—now let’s get practical about evidence. Modern presenters face two problems at the same time: we’re in an Age of Distraction (people will escape to the internet, even while “listening”), and an Era of Cynicism(audiences are more sensitive than ever to whether information is valid). 

Why is evidence more important now than ever?

Because opinion won’t hold attention—and it won’t survive cynicism. If your talk is mostly “editorial” (your views), people either disengage or multitask. If you don’t provide concrete insights backed by proof, hands reach for phones fast. 

Do now: Audit your draft. Highlight anything that is “opinion” and ask: “Where’s the proof?” 

What makes evidence credible in the “Era of Cynicism”?

Credibility comes from quality and transparency: use highly credible sources, use multiple sources, and explain how findings were assembled. Your own research can help, but it may be greeted with doubt if you can’t explain your method. The point is to make listeners feel: “This is checkable.” 

Do now: If you cite your own research, add one line on how it was done (sample, method, timeframe). 

What are the best types of evidence to use in presentations?

Use the DEFEATS framework to choose evidence that convinces busy, skeptical audiences. DEFEATS is a checklist of evidence types you can use to prove what you’re saying is true: Demonstration, Example, Facts, Exhibits, Analogies, Testimonials, Statistics. 

Do now: For each key point in your talk, pick at least one DEFEATS proof type (two if the audience is skeptical). 

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

Each type does a different job—so match the type to the point you’re making. 

• D — Demonstration: show something physically or on-screen (software/audio/video) that reinforces your point. It must be congruent with the message. 
• E — Example: choose examples that are relevant to the audience—same industry, similar organisation size—so people can relate. 
• F — Facts: facts must be provable and independently verifiable. A claim is not a fact. If you use graphs, display the data source clearly (people like knowing they could verify it). 
• E — Exhibits: show a physical object (or image). Make it easy to see: hold it around shoulder height, keep it still. 
• A — Analogies: simplify complexity by comparing two unrelated things (e.g., flight takeoff/landing vs speech opening/closing). 
• T — Testimonials: social proof adds credibility—especially when it comes from recognised experts. It’s not the primary proof, but it strengthens belief. 
• S — Statistics: third-party stats are strongest; your own stats are fine, but less convincing without independent numbers too. 

Do now: Add sources to your slides (small but visible). Make “checkable” part of your credibility. 

What’s the biggest evidence mistake presenters make?

Using examples the audience can’t relate to—or presenting “facts” without checkable sourcing. A senior executive using examples from a major organisation can miss the room if the audience is SMEs. And if you show graphs without citing where the data came from, you quietly trigger doubt. 

Do now: Ask, “Is my example their world?” If not, swap it for one that matches audience size/industry. 

Conclusion

In today’s distracted and cynical environment, evidence is what keeps people with you to the end. Design your key points, then deliberately “match” each one with credible proof—preferably multiple sources—using DEFEATS as your checklist. Do that, and you’ll hold attention and trust at the same time. 

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) and Purezen no Tatsujin (プレゼンの達人).

Greg also publishes daily business insights on LinkedIn, Facebook, and Twitter, and hosts six weekly podcasts. On YouTube, he produces The Cutting Edge Japan Business Show, Japan Business Mastery, and Japan’s Top Business