Supporting Material

Reasons why we need support

• To develop and illustrate ideas

Assertions that lack support are weak. For example, we may assert that nitrogen fertilizer has serious consequences for the environment; however, such an assertion hanging by itself lacks persuasive power. The following would be better:

The massive introduction of nitrogen fertilizer into the soils and waters of the world causes massive environmental problems, ranging from local health problems to global changes that may ultimately wipe out the human race. Not only that the problems extend from deep underground to high in the stratosphere. High nitrate levels cause blue baby disease and some types of cancer. In addition, nitrogen contributes to the depletion of the ozone layer which results in highly increase risk of skin cancer. Currently, high levels of nitrates are contaminating the wells of the Corn Belt and the groundwater of Western Europe, making the water impossible to drink. Many rivers suffer from runaway growth of algae and bacteria which rob the waters of their oxygen content, resulting in the reduction or elimination of fish and crustaceans. Fertilizer runoff has already affected Long Island Sound and San Franciscon Bay. The stratospher is also affected. Nitrous oxide resulting from the action of bacteria on nitrates in the soil contributes to both the depletion of the ozone layer and to global warming. At this very moment cases of skin cancer in Australia, which is most affected by ozone depletion, are rising at an alarming rate. Even now, we are seeing evidence of the effects of global warming with climate changes. In the not too distant future some cities close to the ocean may be under water. Already, massive floods in the Mississippi drainage area have caused billions of dollars of damage.

To clarify ideas

Some ideas are difficult to get across, especially if they are technical in nature. Explaining the meaning of technical terms such as "pointers" in the computer languages C and C++ is a difficult task, but can be done with the use of analogies and illustrations. One concept that people have a difficult time understanding is "sampling" in statistics. Statisticians come to conclusions about people and things based on a relatively small sample from a much larger population. Most people believe that a sample size of 50,000 from a group of one million is much better than a sample size of 500 from the same group. However, this is not true. If you were trying to explain this in a speech you might try the following:

Suppose that you are a compulsive coin flipper. Not only that, you're even crazier and keep meticulous records of how many times your flipping results in heads versus how many times it results in tails. There is a fifty percent chance that you'll get heads. To test this, you can try flipping 20 times and may very well not come up with fifty-fifty results. However, the more you flip, the more the results are fifty-fifty. Can you agree that after 500 flips, you will get close to fifty-fifty? If you can't, try it. I can tell you right now, however, that it will be close. What if you flip 5,000 times? You'll be closer, but is the difference worth the expenditure of time and energy? What about five million times? The point is that, if we are willing to accept a little inaccuracy in our estimates, we don't have to take a sample of more than 500 out of a pool of several million. A sample of 5,000 is just more of the same with diminishing returns.

"Well," you say, "that's just coins. What do you expect?" Okay, let's try marbles. Imagine that you ordered 1,000,000 marbles from the Little Rounder Marble Company. 500,000 were red; 300,000 white, and 200,000 black. On the way to your house, there was a train wreck and all of the marbles ended up getting mixed up so that they were randomly distributed. You want to know if you got the proportions you ordered; so, you naturally ask one of your blind employees to help count the marbles by reaching in the box and drawing out marbles at random. Would the employee have to take all of the marbles out of the box to get an idea of whether you got what you ordered? Would 300 or 500 do the job? Would drawing out 50,000 give a much better idea of the proportions? No, it wouldn't. After a couple of hundred marbles you can get a good idea of how many of each color you have and send your blind employee back to testing light bulbs.

To add interest

People like stories and people are interested in other people. People are more influenced by interesting personal examples than by statistics. That's why anecdotal evidence, especially as we see it on television, is more powerful than sheer numbers. Although statistical data show that it is more dangerous to drive ten or twenty miles in a car to the airport than it is to fly three thousand miles across the country, most people are more apprehensive while flying than when driving to the airport in heavy traffic. One major contributor to the apprehension is the images of plane crashes we see on television which reinforce any fear of flying we may have. If we stop and think about it, the allure of television and other media is our overriding interest in stories about people. This means that you need to personalize your data. If you want to give a speech about the dangers of radiation at K-25, rely on stories about friends, family members, etc., who have been affected and use statistical data secondarily.

To help audience remember

After years of lecturing, I've found that students often remember my little stories more than the plain facts. Supporting materials, especially in the form of narratives are an aid to recall. I once had a student bring an three foot long alligator to class as a visual aid for an informative speech about Cayman Alligators. I've not forgotten it, and I'm sure that the other students in class will never forget it. In fact, I even remember some of what was said about the gators. For example, they eat fish (lucky for us) and their sex is determined by the temperature of the sand in which their eggs incubate.

Types of supporting materials

Definitions

Much of what we learn in school is definitions. Mathematical formulae are definitions of procedures. When we study biology, we study definitions of animals and plants. Psychology is mainly definitions. Our whole intellectual being is dependent upon definitions, of our concepts of reality. Since definitions aare important, they come in several varieties.

1. A dictionary definition is the most obvious. There are problems with dictionary definitions, however. First, since a dictionary definition describes how people in general use a word, the definitions are often too general. In addition, dictionary definitions are often dry and boring. Sometimes the words in the definition need defining. According to Websters Seventh Collegiate Dictionary the word "dignity" is the quality or state of being worthy, honored or esteemed. Borrrrriinnnggg! It would be much better to describe a dignified person as an example of the meaning of dignity [Insert example here.]
   
2. Defining in your own words is effective because it makes the definition more personal and often times put into simpler words than a dictionary definition. "By 'rhetoric' I mean all the means necessary to persuade people to do or believe something."
   
3. You may also define words negatively. Such definitions set the boundaries of what a word means, which is what the word "definition" means anyway. For example, "By 'research' I do not mean going to the drugstore, picking up a magazine, and copying the ideas and words of the first article you see that looks like it might acceptable enough to make into a speech." This statement obviously means that such practice is forbidden. Another example: "When I talk about gun control, I'm not talking about taking away people's right to bear arms by taking away everybody's guns. No. I'm talking about getting control of criminal possession and use of weapons even more powerful than what the police have in their arsenal. I'm talking about taking back the streets so that honest, hard working people do not have to fear walking down the sidewalk at night."
   
4. Sometimes we may want to define a word from its origins. Let's assume that we want to define the word "tantalizing" in a speech. Here's an example. "Drugs such as heroin and cocaine are tantalizing both before a person tries them and forever afterward. What do I mean by that, you ask? Well let's look at where the word came from. It's an ancient Greek word. The story goes that a king by the name of Tantalus betrayed Zeus (the main god of Greek mythology), and as punishment Zeus sentenced him to hang for eternity from the branch of a fruit tree spread over a pool of clear, cool water. Whenever Tantalus got hungry and reached for the fruit the wind would blow it out of his reach. Whenever he got thirsty and leaned over to drink, the water would recede from his reach. That's the way cocaine and heroin are. You may be tantalized into seeking their pleasures, but the more you seek, the more the pleasures recede--until there is nothing but misery, pain, and hunger for the drug left. Don't be tantalized or Zeus may sentence you to a similar fate."
5. We may also define words from their origins. If a word has an interesting origin such a definition may be memorable. For example, the word "funky" came to us via the original capital of funk, New Orleans. New Orleans had a large French and Creole speaking population, which is where the word "funk," which was first "funqier," a word which meant sweaty, smelly, offensive odor. The music played by black bands in the dancehalls caused people to sweat and steam a lot. As a result, the music was called "funky music." Since the music had a heavey backbeat, music such as played by James Brown with it's heavey backbeat and accents on two and four of each measure became known as funk. So, when I talk about funky music, I mean music that makes you sweat, steam, and smell downright bad, not just music with a backbeat."
   
6. Defining by example is often useful. For example, this is an example of defining by example. The previous statement is an example of a self-referential statement. For example, "This statement is false," is a self-referential statement. The previous statement was a definition by example, which is true.
   
7. We often define words by examining their context.
   
8. Defining by analogy refers to comparing two unlike things. For example, we may define nuclear fission by comparing it to a rack of billiard balls being struck by cue ball.
   
9. An operational definition is often a good way to describe an abstract term. For example, "intelligence" is often defined as the score one gets on an intelligence test.

Statistics

Statistics can provide powerful support, but they have their problems. First, numbers can cause people's eyes to glaze over. Second, people generally don't understand anything but the most basic descriptive statistics. Third, people often mistrust them because they've heard they are misused. Fourth, they are sometimes misused by people who don't understand them.

For example, people often don't understand what an average is. Although the average is the most popular kind of statistic, many people don't know that there re three kinds of averages: mean, median, and mode. [more to come]

• Correlations
  

• Percentages
  

• Standard deviations
  

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© Robert Gwynne 1999