Types of Evidence

1. Types of Evidence

Evidence is facts and details that support an argument. While evidence may be useful in any mode of writing, it’s particularly important when you’re making an argument because evidence is how you’ll support your claims and convince your readers to agree with you.

When you’re making an argument, there are two main kinds of evidence that you might use:

• Personal evidence
• Researched evidence

term to know

Evidence

Facts and details that support an argument.

1a. Personal Evidence

Personal evidence is evidence that you draw from your own experience of the world. This means that you might tell a personal narrative.

EXAMPLE

When I was 10, a dog bit me. And after that, I was afraid of dogs.

However, if you’re using your own experience as evidence, there is one big problem. You could say your argument is true because this happened to you, but someone else could refute that by responding, “Your argument is false because that didn’t happen to me.”

Thus, you want to use personal narrative very carefully, and use it to illustrate rather than justify. That means that you’re presenting your experience not as proof, but as an example of how your argument might be believable.

Instead of saying, “My argument is true because this happened to me,” you want to say, “My argument is believable because it can happen, just as it did to me.” In this way, you’re making your experience relatable to your reader, so be sure to use an experience that’s not too specific or unique.

When you use your personal evidence, you might also make it hypothetical, meaning you’re presenting a situation that could happen as an illustration that supports your argument. For hypothetical evidence, you would be saying, “My argument is believable because it can happen, just as it could in this hypothetical way.” Again, make sure that you use relatable and believable experiences.

Finally, you can also draw on common knowledge. If you can reasonably believe that your readers will have had an experience or know a fact, then you can call upon that.

EXAMPLE

An author might use an example about playing poker because he or she can reasonably expect that most readers will know what the game of poker is.

Consider the following argument:

You might then use a personal narrative to say:

See how this experience is used as an illustration of why the argument is believable? It doesn’t matter if the reader was never bitten by a dog. The experience used as personal evidence is rational, relatable, and believable.

You could also make a similar experience into a hypothetical:

term to know

Personal Evidence

Evidence drawn from your own experience of the world.

1b. Researched Evidence

If you don’t have an experience to share as an example, and you can’t think of a hypothetical experience that would support your argument, you’ll want to do some research to find evidence that supports your claim.

Research means finding facts, data, statistics, and ideas from other writers and sources in order to support your ideas; researched evidence is evidence that you have found in other sources.

When you research, you look in books and newspapers, on websites, and in scholarly journals and experiments to find information that helps you make a convincing argument.

Researched information might be:

• Expert arguments: These are the theories, arguments, or ideas proposed by an expert in the field.
  
  

  EXAMPLE

  If you’re writing a paper about psychology, you might use evidence from publications such as the American Journal of Psychiatry.

• Research findings: These are data from surveys or research experiments.
  
  

  EXAMPLE

  If you’re writing about school lunch programs, you might use evidence from the US Department of Education about how many students use school lunches nationwide.

• First person data: This is someone else’s first person experience of something.
  
  

  EXAMPLE

  If you’re writing an argument for increased funding for the Veterans Administration, you might use an interview with a veteran to describe why the VA is important to so many.

All of these types of research can be useful and lead you to the application of good researched evidence.

terms to know

Research

Finding facts, data, statistics, and ideas from other writers and sources in order to support our own ideas.

Researched Evidence

Evidence that you have found in other sources.

2. Evaluating Research

Of course, not all research is good or convincing. Good data should be:

• Current
• Relevant
• Unbiased
• Rational

Your data needs to be relevant because it must be able to directly relate to your argument.

EXAMPLE

If you want to make an argument for leash laws, data about zoos might not be particularly useful. You would need to find a source that is directly relevant to your argument.

Note that your source doesn’t necessarily need to make the exact argument you're making, but it does need to be related to your general topic.

Your data needs to be unbiased because if your source is clearly biased one way or another, then the evidence it contains might not be trustworthy. Think of the informative mode of writing; it presents data in an unbiased manner without taking a side on the issue. That’s what you want to use to take a side of your own and support that side believably and ethically.

Finally, your data needs to be rational, as some sources simply aren’t rational, informed, or expert.

EXAMPLE

You may personally have a lot of opinions about orcas or killer whales, but you should not be cited as a rational source if you don’t actually have any real expertise about them. Your evidence would all be based on opinion, which can be very wrong.

Similarly, some sources, such as conspiracy theories, hold purely irrational beliefs that are not supported by fact. You want to avoid referencing those sources.

3. Locating Sources and Avoiding Bias

When looking for sources, news reports are often a good place to start. They may contain good summaries of information, which you can use directly in your essay or which can guide you towards other sources.

Beware, however, of bias. Though the news can seem neutral, it is often colored by political or social biases. You want to make sure that your source is not partisan.

Libraries and library websites can be very useful for finding scholarly articles and books. Once you find a good book or article, the bibliography in that book can lead you to other resources as well.

Websites can also have a wealth of information. Blogs and commercial websites might not be unbiased, but they might provide useful first-person data. In contrast, websites that end in .gov or .edu can be full of more neutral and detailed research findings.

Even Wikipedia can be a good place to start your research, but it is not a valid academic source because anyone can edit any page, meaning the information can’t be verified.

When looking at a source, you should ask yourself:

• Who wrote this and when?
  • Getting a sense of who this author is and what the context of the piece is will be very informative and tell you if it’s current, unbiased, and rational.
• Who published this?
  • If you’re looking at a website or a news article, check what’s called the “masthead” of that publication. A masthead is a list of who is involved in the publication as well as contact information. You might look for a link that says “About Us” or something similar if you’re on a web page.
  • You can also search for that news source and look at its Wikipedia page, which will tell you more about the source. This is a good way to make sure that you are getting unbiased resources and that you’re not accidentally citing humor or satire.
• What are the methods?
  • To answer this, look for a section called “Methodology.” This is particularly important for research experiments, polls, and other data. If the methods indicate that the research has a very narrow scope but is being applied broadly, that’s a warning sign that this isn’t reliable information.
• What kind of information does this source cite?
  • If you look at its bibliography, do you see good, trustworthy sources, or do those sources appear biased?