Evidence and Source Selection

Types of Evidence and their Usefulness As we saw previously, evidence, facts, examples, statistics, and other concrete details are an important part of an essay. Consider: what kinds of evidence is frequently used to support a thesis?

Types of Evidence and their Usefulness Here is a list of the most common types of evidence: Personal experience Case examples/studies Testimonials Appeals to authority Research studies Analogies Which of these do you think is most appropriate for a research paper?

Types of Evidence and their Usefulness The two that should stand out are appeals to authority, research studies, and sometimes case studies. The others, though often used in other forms of writing, don’t really work as well with research writing.

Types of Evidence and their Usefulness Personal experience and its problems: Personal experience is not representative of anything except the person’s own individual experience. Research papers often require students to refer to evidence that is broadly representative of what they are discussing. Personal experience fails to do that. When a person uses personal experience to bolster an argument or in place of research, problems frequently occur.

Types of Evidence and their Usefulness Personal experience and its problems: Consider the following example: “In my classroom this year, I’ve noticed that almost all of the students who have a learning disability are left handed. This strongly suggest that being left- handed is a strong indicator of a learning disability in most students.” What’s wrong with this argument?

Types of Evidence and their Usefulness Personal experience and its problems: The problems with the preceding argument lie largely in the use of personal experience as evidence to suggest a large trend. The evidence is only the student’s experience with her own classroom, yet she uses it to generalize about all students. It’s possible that the by simple random chance that most of the students with learning disabilities turned out to be left-handed in this particular classroom, and without larger studies that represent a larger population of students.

Types of Evidence and their Usefulness Problems with testimonials as evidence. Largely, testimonials are individuals speaking on record about the positives of a concept, method, or product. The problems with testimonials are similar to the problems with personal experience. They are often not representative. Testimonials are often “cherry picked” to reflect only the positive. Conflict of interest: sometimes the person giving the testimonial has been paid to do so or has some other incentive.

Types of Evidence and their Usefulness Consider the following argument taken from an ad campaign from an ad campaign about abstinence-only sex education: “I am thoroughly pleased with the abstinence-only sex education curriculum. Both of my sons went through the program here in Texas, and neither one had premarital sex until he was married and ready to start a family. Also, neither one of them has contracted a sexually transmitted disease. Evidence like this proves that abstinence-only programs should be the model that school districts across the country should use.” What’s wrong with this argument?

Types of Evidence and their Usefulness Again, the problems with this argument lie in the evidence. The experience of the person giving the testimonial is only representative of her two sons. Other children enrolled in the program may have had different outcomes. If we just rely on this testimonial, we have no way of knowing whether most of the students in the program as a whole had positive results. Also, the testimonial is for an ad campaign, and may have been selected because it is positive, with the makers of the ad possibly ignoring others who would speak differently about the program.

Types of Evidence and their Usefulness Analogies (comparisons between two things meant to show similarities) are also problematic when the analogy isn’t backed up by research.

Types of Evidence and their Usefulness Appeals to authority are better forms of evidence for research papers because of the person’s credentials. However, be careful of citing experts who have no credentials or experience in the area they are speaking on. For example, “My stock broker took a look at my symptoms and suggests that I have liver disease.” This stock broker is not a credible source in this case because he’s giving medical advice, something he has no expertise in.

Types of Evidence and their Usefulness Research studies are also very helpful for research papers. However, do read carefully. The statistics in these studies can be misleading. Consider the following argument: “The crime rate in our town has tripled. This is clear evidence that we’re part of a national crime wave.” The deception comes in when the reader takes a look at the population of the town and the number of crimes committed. Town: population 1,000. Number of crimes committed last year: 1. Number of crimes committed this year: 3. While the person making this claim is technically correct that the crime rate tripled. It is dubious that three crimes constitute a “crime wave.” This argument uses a research study, but uses it deceptively.

Types of Evidence and their Usefulness Case Studies: Case studies are studies of individual cases of a situation. They can be emotionally powerful, but used by themselves, like personal experience, they are far from representative.

Sources and Source Selection So with this information, it’s clear that the student needs to be careful in selecting sources. This begs the question, “what should a student look for in a good source?” While not fool-proof, the following list of considerations will make it more likely that the student will find good, credible sources.

Sources and Source Selection Good sources tend to be published by a reputable press or publisher. Most university presses or publishers from accredited schools are reliable. These publishers put out academic books, articles, and research studies. Good academic publishers usually peer review everything they publish so that other experts in the field can evaluate the quality of the work. Good sources are usually written by credible scholars with credentials appropriate to the field they are writing about. Good sources are also current, especially with research studies.

A Closing Note: With this in mind, filtering the sources that you consider for your paper should be much easier. When you settle on your topic and start researching your topic in earnest, this will provide a helpful guide for your selection of sources.