Forms of Evidence

Types of evidence your book lists:

1. Facts
2. Statistics
3. Testimony
4. Anecdotal evidence
5. Scenarios
6. Case studies and observation
7. Textual evidence

This is a start . . . but many people find themselves confused by such lists, wondering what the difference is between a "study" and "observation" and how facts, for instance, might different from statistics (aren't these facts, too?) and which kinds of "anecdotal" evidence might be appropriate.

1. Experiential knowledge: when we're talking about the kinds of experience people have, and how that experience segues into being a source worth using or not. This kind of knowledge and experience usually falls under the heading "anecdotal" evidence. When we're talking personal experience (that YOU, not your friends or family members) have had, sometimes it is relevant in an argument. You CAN use first-person in the rest of the papers as long as it's demonstrably relevant. You should use first-person ONLY if you are chronicling a personal experience that highlights something about your argument. This kind of knowledge -- having had personal experience with something -- is one type of "expert" knowledge. It is, as you know, not the strongest form of evidence. The other is what I like to call "professional knowledge". If, for instance, I bring my teaching experience into a paper, I can talk about teaching writing and literature from a perspective that is both personal AND professional. A sociology professor might be able to talk about what it's like to be an urban black youth (even if that professor is not black, urban, or young) in a way that is significant because he/she has studied this identity professionally. A young, urban black student can talk about this from a PERSONAL but not professional standpoint. Ultimately, make a distinction between personal experience and professional knowledge. You always need to keep in mind your evidence's context: not just what it is but from whom it's coming and under which circumstances. To recap: yes, you can use personal experience in a limited way in your papers. Yes, you can use professional opinions/knowledge whether these come from interviews, quotes from magazines and journals, etc.

2. Another common question: aren't statistics "facts"? Not always. Can you use statistics? Absolutely. But carefully. Statistics can be misused, and they are not always factual: this depends on a number of things -- sample size, demographic, etc. You can use statistics, but be aware that statistics, while they sound convincing, are usually "spun" in a way that fits the writer/arguer's purpose. When you use statistics, you always need to explain the context surrounding the number: it's not enough to say "Eighty percent of people voted for Obama". Eighty percent of registered voters? Eighty percent of the population of the United States? How was this number calculated? How were the results measured? etc. You must provide some information of this ilk for your statistic to be credible. They are not facts in the same way that "the sky is blue". Keep this in mind, and your statistical use will be stronger. (When you're reading, pay special attention to how authors use statistics. See if you can find any holes or gaps in logic in terms of how they are used.)

3. Testimony is a form of personal experience and is anecdotal -- it can be either personal or professional, or both. It is unlikely you will use a lot of testimony in the kinds of papers you are writing.

4. Scenarios: Spelling out scenarios involves a very important form of evidence: your own logic (not included in the text list). You would provide a scenario if you wanted to set up a picture for your readers that will illustrate what could/is likely to occur. These, too, like anecdotal evidence, are not the strongest form of evidence because they can't be quantified and there's no guarantee that things will turn out according to a scenario. I've seen scenario examples work well in papers students have written about the housing market, Wall Street and the like. Example: "If everyone in America cut credit card spending by X percent, the economy would falter/tank/improve, etc. Well, there's no way to make every person automatically cut spending by any much less a specific percent, so there's no way to use scenarios as facts. You CAN use them to provide a general picture of the ebb and flow of circumstances.

5. We'll put case studies, observation, and textual evidence all together. These forms of evidence are your strongest, most credible, and most likely necessary for the kind of writing you're doing. Where do you find these? Well, the world-wide web is a good place to start, but your STRONGEST evidence is going to be that which you take from scholarly journals and books. You will find these forms of evidence in the library's database. I have posted a handout on our website that explains the difference between popular and scholarly sources. This will be very important for the third and fourth papers, so take a look when you can. We will begin discussing this at length very soon. In the meantime, I hope this discussion gives you a clearer of sense of what "counts" as evidence, and which forms should be used sparingly.