Chapter 9 Public Speaking

9.5 Supporting Ideas in Your Speech


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Every day, all around the country, people give speeches that contain generalities and vagueness. Students on your campus might claim that local policies are biased against students, but may not explain why. Politicians may make claims in their speeches about “family values” without defining what those values are or throw out statistics without giving credit to where they found those numbers. Indeed, the nonpartisan websites and are dedicated to investigating and dispelling the claims that politicians make in their speeches.

In this chapter, we explore the nature of supporting ideas in public speaking and why support is essential to effective presentations. We will then discuss how to use support to build stronger arguments within a speech.

Why We Use Support

Speakers use support to help provide a foundation for their message. You can think of support as the legs on a table. Without the legs, the table becomes a slab of wood or glass lying on the ground; as such, it cannot fully serve the purpose of a table. In the same way, without support, a speech is nothing more than fluff. Audience members may ignore the speech’s message, dismissing it as just so much hot air. In addition to being the foundation that a speech stands on, support also helps us clarify content, increase speaker credibility, and make the speech more vivid.

To Clarify Content

The first reason to use support in a speech is to clarify content. Speakers often choose a piece of support because a previous writer or speaker has phrased something in a way that evokes a clear mental picture of the point they want to make. For example, suppose you’re preparing a speech about hazing in college fraternities. You may read your school’s code of student conduct to find out how your campus defines hazing. You could use this definition to make sure your audience understands what hazing is and what types of behaviors your campus identifies as hazing.

To Add Credibility

Another important reason to use support is because it adds to your credibility as a speaker. The less an audience perceives you as an expert on a given topic, the more important it is to use a range of support. By doing so, you let your audience know that you’ve done your homework on the topic.

At the same time, you could hurt your credibility if you use inadequate support or support from questionable sources. Your credibility will also suffer if you distort the intent of a source to try to force it to support a point that the previous author did not address. For example, the famous 1798 publication by Thomas Malthus, An Essay on the Principle of Population, has been used as support for various arguments far beyond what Malthus could have intended. Malthus’s thesis was that as the human population increases at a greater rate than food production, societies will go to war over scarce food resources (Malthus, 1798). Some modern writers have suggested that, according to the Malthusian line of thinking, almost anything that leads to a food shortage could lead to nuclear war. For example, better health care leads to longer life spans, which leads to an increased need for food, leading to food shortages, which lead to nuclear war. Clearly, this argument makes some giant leaps of logic that would be hard for an audience to accept.

For this reason, it is important to evaluate your support to ensure that it will not detract from your credibility as a speaker. Here are four characteristics to evaluate when looking at support options: accuracy, authority, currency, and objectivity.


One of the quickest ways to lose credibility in the eyes of your audience is to use support that is inaccurate or even questionably accurate. Admittedly, determining the accuracy of support can be difficult if you are not an expert in a given area, but here are some questions to ask yourself to help assess a source’s accuracy:

  • Does the information within one piece of supporting evidence completely contradict other supporting evidence you’ve seen?
  • If the support is using a statistic, does the supporting evidence explain where that statistic came from and how it was determined?
  • Does the logic behind the support make sense?

One of this book’s authors recently observed a speech in which a student said, “The amount of pollution produced by using paper towels instead of hand dryers is equivalent to driving a car from the east coast to St. Louis.” The other students in the class, as well as the instructor, recognized that this information sounded wrong and asked questions about the information source, the amount of time it would take to produce this much pollution, and the number of hand dryers used. The audience demonstrated strong listening skills by questioning the information, but the speaker lost credibility by being unable to answer their questions.


The second way to use support in building your credibility is to cite authoritative sources—those who are experts on the topic. In today’s world, there are all kinds of people who call themselves “experts” on a range of topics. There are even books that tell you how to get people to regard you as an expert in a given industry (Lizotte, 2007). Today there are “experts” on every street corner or website spouting off information that some listeners will view as legitimate.

So what truly makes someone an expert? Bruce D. Weinstein, a professor at West Virginia University’s Center for Health Ethics and Law, defined expertise as having two senses. In his definition, the first sense of expertise is “knowledge in or about a particular field, and statements about it generally take the form, ‘S is an expert in or about D.’… The second sense of expertise refers to domains of demonstrable skills, and statements about it generally take the form, ‘S is an expert at skill D (Weinstein, 1993).’” Thus, to be an expert, someone needs to have considerable knowledge on a topic or considerable skill in accomplishing something.

As a novice researcher, how can you determine whether an individual is truly an expert? Unfortunately, there is no clear-cut way to wade through the masses of “experts” and determine each one’s legitimacy quickly. However, Table 8.1 “Who Is an Expert?” presents a list of questions based on the research of Marie-Line Germain that you can ask yourself to help determine whether someone is an expert (Germain, 2006).

Table 8.1 Who Is an Expert?

Questions to Ask Yourself Yes No
1. Is the person widely recognizable as an expert?
2. Does the person have an appropriate degree/training/certification to make her or him an expert?
3. Is the person a member of a recognized profession in her or his claimed area of expertise?
4. Has the person published articles or books (not self-published) on the claimed area of expertise?
5. Does the person have appropriate experience in her or his claimed area of expertise?
6. Does the person have clear knowledge about her or his claimed area of expertise?
7. Is the person clearly knowledgeable about the field related to her or his claimed area of expertise?
8. When all is said and done, does the person truly have the qualifications to be considered an expert in her or his claimed area of expertise?

You don’t have to answer “yes” to all the preceding questions to conclude that a source is credible, but a string of “no” answers should be a warning signal. In a Columbia Journalism Review article, Allisa Quart raised the question of expert credibility regarding the sensitive subject of autism. Specifically, Quart questioned whether the celebrity spokesperson and autism advocate Jennifer McCarthy ( qualifies as an expert. Quart notes that McCarthy “insists that vaccines caused her son’s neurological disorder, a claim that has near-zero support in scientific literature” (Quart, 2010). Providing an opposing view is a widely read blog called Respectful Insolence (, whose author is allegedly a surgeon/scientist who often speaks out about autism and “antivaccination lunacy.” Respectful Insolence received the 2008 Best Weblog Award from MedGagdet: The Internet Journal of Emerging Medical Technologies. We used the word “allegedly” when referring to the author of Respectful Insolence because as the website explains that the author’s name, Orac, is the “nom de blog of a (not so) humble pseudonymous surgeon/scientist with an ego just big enough to delude himself that someone, somewhere might actually give a rodent’s posterior about his miscellaneous verbal meanderings, but just barely small enough to admit to himself that few will” (ScienceBlogs LLC).

When comparing the celebrity Jenny McCarthy to the blogger Orac, who do you think is the better expert? Were you able to answer “yes” to the questions in Table 8.1 “Who Is an Expert?” for both “experts”? If not, why not? Overall, determining the authority of support is clearly a complicated task, and one that you should spend time thinking about as you prepare the support for your speech.


The third consideration in using support to build your credibility is how current the information is. Some ideas stay fairly consistent over time, like the date of the Japanese attack on Pearl Harbor or the mathematical formula for finding the area of a circle, but other ideas change wildly in a short period of time, including ideas about technology, health treatments, and laws.

Although we never want to discount classic supporting information that has withstood the test of time, as a general rule for most topics, we recommend that information be less than five years old. Obviously, this is just a general guideline and can change depending on the topic. If you’re giving a speech on the history of mining in West Virginia, then you may use support from sources that are much older. However, if you’re discussing a medical topic, then your support information should probably be from the past five years or less. Some industries change even faster, so the best support may come from the past month. For example, if are speaking about advances in word processing, using information about Microsoft Word from 2003 would be woefully out-of-date because two upgrades have been released since 2003 (2007 and 2010). As a credible speaker, it is your responsibility to give your audience up-to-date information.


The last question you should ask yourself when examining support is whether the person or organization behind the information is objective or biased. Bias refers to a predisposition or preconception of a topic that prevents impartiality. Although there is a certain logic to the view that every one of us is innately biased, as a credible speaker, you want to avoid just passing along someone’s unfounded bias in your speech. Ideally you would use support that is unbiased; Table 8.2 “Is a Potential Source of Support Biased?” provides some questions to ask yourself when evaluating a potential piece of support to detect bias.

Table 8.2 Is a Potential Source of Support Biased?
Questions to Ask Yourself Yes No
1. Does the source represent an individual’s, an organization’s, or another group’s viewpoint?
2. Does the source sound unfair in its judgment, either for or against a specific topic?
3. Does the source sound like personal prejudices, opinions, or thoughts?
4. Does the source exist only on a website (i.e., not in print or any other format)?
5. Is the information published or posted anonymously or pseudonymously?
6. Does the source have any political or financial interests related to the information being disseminated?
7. Does the source demonstrate any specific political orientation, religious affiliation, or other ideology?
8. Does the source’s viewpoint differ from all other information you’ve read?

As with the questions in Table 8.1 “Who Is an Expert?” about expertise, you don’t have to have all “no” or “yes” responses to decide on bias. However, being aware of the possibility of bias and where your audience might see bias will help you to select the best possible support to include in your speech.

To Add Vividness

In addition to clarifying content and enhancing credibility, support helps make a speech more vivid. Vividness refers to a speaker’s ability to present information in a striking, exciting manner. The goal of vividness is to make your speech more memorable. One of the authors still remembers a vivid example from a student speech given several years ago. The student was speaking about the importance of wearing seat belts and stated that the impact from hitting a windshield at just twenty miles per hour without a seat belt would be equivalent to falling out of the window of their second-floor classroom and landing face-first on the pavement below. Because they were in that classroom several times each week, students were easily able to visualize the speaker’s analogy and it was successful at creating an image that is remembered years later. Support helps make your speech more interesting and memorable to an audience member.

Types of Support

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Now that we’ve explained why support is important, let’s examine the various types of support that speakers often use within a speech: facts and statistics, definitions, examples, narratives, testimony, and analogies.

Factual Material: Facts, Statistics & Definitions

A fact is a truth that is arrived at through the scientific process. Speakers often support a point or specific purpose by citing facts that their audience may not know. A typical way to introduce a fact orally is “Did you know that…?”

Many of the facts that speakers cite are based on statistics. Statistics is the mathematical subfield that gathers, analyzes, and makes inferences about collected data. Data can come in a wide range of forms—the number of people who buy a certain magazine, the average number of telephone calls made in a month, the incidence of a certain disease. Though few people realize it, much of our daily lives are governed by statistics. Everything from seat-belt laws, to the food we eat, to the amount of money public schools receive, to the medications you are prescribed are based on the collection and interpretation of numerical data.

It is important to realize that a public speaking textbook cannot begin to cover statistics in depth. If you plan to do statistical research yourself, or gain an understanding of the intricacies of such research, we strongly recommend taking a basic class in statistics or quantitative research methods. These courses will better prepare you to understand the various statistics you will encounter.

However, even without a background in statistics, finding useful statistical information related to your topic is quite easy. Table 8.3 “Statistics-Oriented Websites” provides a list of some websites where you can find a range of statistical information that may be useful for your speeches.

Table 8.3 Statistics-Oriented Websites

Website Type of Information Bureau of Labor Statistics provides links to a range of websites for labor issues related to a vast range of countries. Bureau of Justice Statistics provides information on crime statistics in the United States. US Census Bureau provides a wide range of information about people living in the United States. National Center for Health Statistics is a program conducted by the US Centers for Disease Control and Prevention. It provides information on a range of health issues in the United States. STATS is a nonprofit organization that helps people understand quantitative data. It also provides a range of data on its website. Roper Center for Public Opinion provides data related to a range of issues in the United States. Nielsen provides data on consumer use of various media forms. Gallup provides public opinion data on a range of social and political issues in the United States and around the world. Adherents provides both domestic and international data related to religious affiliation. Pew Research Center provides public opinion data on a range of social and political issues in the United States and around the world.

Statistics are probably the most used—and misused—form of support in any type of speaking. People like numbers. People are impressed by numbers. However, most people do not know how to correctly interpret numbers. Unfortunately, there are many speakers who do not know how to interpret them either or who intentionally manipulate them to mislead their listeners. As the saying popularized by Mark Twain goes, “There are three kinds of lies: lies, damned lies, and statistics” (Twain, 1924).

To avoid misusing statistics when you speak in public, do three things. First, be honest with yourself and your audience. If you are distorting a statistic or leaving out other statistics that contradict your point, you are not living up to the level of honesty your audience is entitled to expect. Second, run a few basic calculations to see if a statistic is believable. Sometimes a source may contain a mistake—for example, a decimal point may be in the wrong place or a verbal expression like “increased by 50 percent” may conflict with data showing an increase of 100 percent. Third, evaluate sources (even those in Table 8.3 “Statistics-Oriented Websites”, which are generally reputable) according to the criteria discussed earlier in the chapter: accuracy, authority, currency, and objectivity.


denotative definition is one that specifically states how a word is used within a specific language. For example, if you go to and type in the word “speech,” here is the denotative (i.e. lexical) definition you will receive:


the faculty or power of speaking; oral communication; ability to express one’s thoughts and emotions by speech sounds and gesture: Losing her speech made her feel isolated from humanity.

the act of speaking: He expresses himself better in speech than in writing.

something that is spoken; an utterance, remark, or declaration: We waited for some speech that would indicate her true feelings.

a form of communication in spoken language, made by a speaker before an audience for a given purpose: a fiery speech.
any single utterance of an actor in the course of a play, motion picture, etc.
the form of utterance characteristic of a particular people or region; a language or dialect.
manner of speaking, as of a person: Your slovenly speech is holding back your career.

a field of study devoted to the theory and practice of oral communication.

Lexical definitions are useful when a word may be unfamiliar to an audience and you want to ensure that the audience has a basic understanding of the word. However, our ability to understand lexical definitions often hinges on our knowledge of other words that are used in the definition, so it is usually a good idea to follow a lexical definition with a clear explanation of what it means in your own words.

Definitions are important to provide clarity for your audience. Effective speakers strike a balance between using definitions where they are needed to increase audience understanding and leaving out definitions of terms that the audience is likely to know. For example, you may need to define what a “claw hammer” is when speaking to a group of Cub Scouts learning about basic tools, but you would appear foolish—or even condescending—if you defined it in a speech to a group of carpenters who use claw hammers every day. On the other hand, just assuming that others know the terms you are using can lead to ineffective communication as well. Medical doctors are often criticized for using technical terms while talking to their patients without taking time to define those terms. Patients may then walk away not really understanding what their health situation is or what needs to be done about it.


Another often-used type of support is examples. An example is a specific situation, problem, or story designed to help illustrate a principle, method, or phenomenon. Examples are useful because they can help make an abstract idea more concrete for an audience by providing a specific case. Let’s examine three types of examples: brief, extended and hypothetical.

Brief Examples[1]

Brief examples are used to further illustrate a point that may not be immediately obvious to all audience members but is not so complex that is requires a more lengthy example. Brief examples can be used by the presenter as an aside or on its own. A presenter may use a brief example in a presentation on politics in explaining the Electoral College. Since many people are familiar with how the Electoral College works, the presenter may just mention that the Electoral College is based on population and a brief example of how it is used to determine an election. In this situation it would not be necessary for a presented to go into a lengthy explanation of the process of the Electoral College since many people are familiar with the process.

Extended Examples

Extended examples are used when a presenter is discussing a more complicated topic that they think their audience may be unfamiliar with. In an extended example a speaker may want to use a chart, graph, or other visual aid to help the audience understand the example. An instance in which an extended example could be used includes a presentation in which a speaker is explaining how the “time value of money” principle works in finance. Since this is a concept that people unfamiliar with finance may not immediately understand, a speaker will want to use an equation and other visual aids to further help the audience understand this principle. An extended example will likely take more time to explain than a brief example and will be about a more complex topic.

Hypothetical Examples

A hypothetical example is a fictional example that can be used when a speaker is explaining a complicated topic that makes the most sense when it is put into more realistic or relatable terms. For instance, if a presenter is discussing statistical probability, instead of explaining probability in terms of equations, it may make more sense for the presenter to make up a hypothetical example. This could be a story about a girl, Annie, picking 10 pieces of candy from a bag of 50 pieces of candy in which half are blue and half are red and then determining Annie’s probability of pulling out 10 total pieces of red candy. A hypothetical example helps the audience to better visualize a topic and relate to the point of the presentation more effectively

Examples are essential to a presentation that is backed up with evidence, and they help the audience effectively understand the message being presented. Examples are most effective when they are used as a complement to a key point in the presentation and focus on the important topics of the presentation. However, a speaker should be careful to not overuse examples, as too many examples may confuse the audience and distract them from focusing on the key points that the speaker is making.


Another form of support you may employ during a speech is testimony. When we use the word “testimony” in this text, we are specifically referring to expert opinion or direct accounts of witnesses to provide support for your speech. Notice that within this definition, we refer to both expert and eyewitness testimony.

Expert Testimony

Expert testimony accompanies the discussion we had earlier in this chapter related to what qualifies someone as an expert. In essence, expert testimony expresses the attitudes, values, beliefs, or behaviors recommended by someone who is an acknowledged expert on a topic. For example, imagine that you’re going to give a speech on why physical education should be mandatory for all grades K–12 in public schools. During the course of your research, you come across The Surgeon General’s Vision for a Fit and Healthy Nation ( You might decide to cite information from within the report written by US Surgeon General Dr. Regina Benjamin about her strategies for combating the problem of childhood obesity within the United States. If so, you are using the words from Dr. Benjamin, as a noted expert on the subject, to support your speech’s basic premise. Her expertise is being used to give credibility to your claims.

Eyewitness Testimony

Eyewitness testimony, on the other hand, is given by someone who has direct contact with the phenomenon of your speech topic. Imagine that you are giving a speech on the effects of the 2010 “Deepwater Horizon” disaster in the Gulf of Mexico. Perhaps one of your friends happened to be on a flight that passed over the Gulf of Mexico and the pilot pointed out where the platform was. You could tell your listeners about your friend’s testimony of what she saw as she was flying over the spill.

However, using eyewitness testimony as support can be a little tricky because you are relying on someone’s firsthand account, and firsthand accounts may not always be reliable. As such, you evaluate the credibility of your witness and the recency of the testimony.

To evaluate your witness’s credibility, you should first consider how you received the testimony. Did you ask the person for the testimony, or did he or she give you the information without being asked? Second, consider whether your witness has anything to gain from his or her testimony. Basically, you want to know that your witness isn’t biased.

Second, consider whether your witness’ account was recent or something that happened some time ago. With a situation like the BP oil spill, the date when the spill was seen from the air makes a big difference. If the witness saw the oil spill when the oil was still localized, he or she could not have seen the eventual scope of the disaster.

Overall, the more detail you can give about the witness and when the witness made his or her observation, the more useful that witness testimony will be when attempting to create a solid argument. However, never rely completely on eyewitness testimony because this form of support is not always the most reliable and may still be perceived as biased by a segment of your audience.


  1. Find an article online about a topic on which you are interested in speaking. Examine it for the four aspects of effective sources (e.g., accuracy, authority, currency, and objectivity). Do you think this source is credible? Why?
  2. Find a speech on the Vital Speeches of the Day website ( and try to identify the types of support the speaker utilized. Is the speaker’s use of support effective? Why or why not?
  3. Look at the speech you are currently preparing for your public speaking class. What types of support are you using? Could you enhance the credibility of your speech by using other types of support? If so, what types of support do you think you are lacking?
  4. Find and analyze a newspaper op-ed piece or letter to the editor that takes a position on an issue. Which types of support does the writer use? How effective and convincing do you think the use of support is? Why?
  5. You’ve been asked to give a speech on child labor within the United States. Provide a list of possible examples you could use in your speech. You should have one from each of the four categories: positive, negative, non, and best.



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