Chapter 6: Being Credible and Using Evidence

I. Types of Supporting Materials  

A.  Facts: Refer to verifiable units of information. Facts can “lie” or mislead.

B.  Examples: There are four kinds:

1.   Factual: An example that is verifiable and taken from a real life scenario

2.   Hypothetical: Use to show a “perfect” example or use when one is not available by asking the audience to “imagine”

a situation. Make sure the audience knows the example was created and isn’t real

3.   Brief: Mentioned in passing

4.   Extended: Stories/narratives; goes beyond the brief example

C.  Surveys: Refer to questionnaires answered by a sample and are reported in numbers and statistics (numerical facts)

     usually.

Tips for using statistics:

1. Use sparingly. Don’t overload people with lots of statistics. People can’t process them easily all at once

2. Quantify ideas: Use statistics to demonstrate the scope or prevalence of a problem

3. Identify sources: Cite with “according to” so people can judge the credibility of your figures

4. Explain: Numbers are abstract. Relate the numbers to the audience in a personal way.

5. Round off your statistics

6. Use visuals, especially if you have lots of statistics

D.  Testimonials: There are three types:

1.   Lay: Testimony “of the people” whereby a “common person” provides an opinion

2.   Expert: Testimony from recognized authorities

3.   Prestige: Testimony from celebrities or public figures

E.  Analogies: Show comparisons and contrasts. Comparisons show similarities. Contrast show differences.

F.  Definitions: Define terms to simplify ideas and concepts for your audience. Avoid jargon or technical terms unless you

     are dealing with an audience educated on your subject.

III.  When to Use What Types of Support?     

A.   If the subject is controversial: Use facts, factual examples, stats, expert testimony

B.   If the subject is abstract: Use examples and analogies

C.   If the subject is technical: Use definitions, analogies, expert testimony

D.   If you wish to arouse emotions: Use lay and prestige testimony, examples, narratives

E.   If you wish to diffuse emotions: Use facts, statistics, expert testimony

F.   If your subject is distant from the lives of listeners:  Use examples, narratives, and analogies

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This page last updated August 21, 2007

Arkansas State University