Page 238 - Between One and Many The Art and Science of Public Speaking
P. 238
Speaking of . . .
Numerical Data
Tests for using numerical data • Consider the margin of error—do the differences
exceed it?
• Know the source—is it unbiased and reliable?
• Know what percentages are based on—are they
• Know what questions were asked—were they fair and
percentages of percentages?
unbiased?
• Know the kind of average used—was it the mean
• Know how the sample was chosen—is it
(average) or the median (midpoint)?
representative?
had terrible complications from breast implant surgery spoke in one of our
classes. Her speech was short on quotes from experts but was still very power-
ful because she told the story of her mother’s suffering in a convincing way. If
we intend to use our own opinions as support in a speech, we need to be sure to
explain to the audience why our opinions are worth considering.
More common than personal opinion in supporting a speech is expert opin-
expert opinion
ion—a quotation from someone with special credentials in the subject matter.
A quotation from
Quotations from experts, whether gathered from a personal interview or from
someone with special
written sources, can be a persuasive way of supporting your points. However, credentials in the subject
you need to ask three basic questions about expert opinion: matter.
• What is the source’s expertise? How do you know this person is an expert? Try
a Google search or look at biographical sources (such as Who’s Who) if you
do not know who the person is. Look for marks of expertise, such as aca-
demic credentials, offi cial positions, or references from other authorities.
Finally, make sure your source is an expert in the subject matter of your
speech. It is important to explain to your audience why the person you are
quoting is an expert they should believe.
• Does the expert have a reputation for reliability? How accurate have the expert’s
previous statements been? If someone has a record of either false or mis-
taken statements in the past, it is misguided to rely on that person’s state-
ments today.
• Is the source unbiased? If a source has a vested interest in one side of a topic,
his or her opinions are automatically suspect. Your audience needs to be
assured that you are not relying on sources who have an axe to grind.
Explanations
An explanation is an account, an interpretation, or a meaning given to some-
thing. Detailed explanations may prove useful in a speech. But to be effective,
explanations must meet three tests:
• Is the explanation clear? A complex or unclear explanation may only confuse
your audience. One way to clarify an explanation is to use comparisons
and contrasts. Thus someone might explain a nuclear power plant by com-
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