Finding and Evaluating Sources

Learning Objectives:

  • Identify and evaluate types of evidence.
  • Identify and evaluate credible sources.
  • Identify reliable online sources.

Providing credibleDescribes a person who is trusted and able to be believed; reliable. evidenceFacts, statistics, or expert testimony that supports a claim. is essential for the success of any analysisTo analyze is to make a thoughtful and detailed study of something. An analysis is the end result of analyzing. or opinion-based argumentA set of statements or reasons making a case for or against something.. Evidentiary supportEvidence that supports the claims or viewpoints expressed in an essay and helps convince readers that an argument has merit. Evidentiary support may take the form of facts and statistics, expert opinions, or anecdotal evidence. is especially crucial to the effectiveness of a persuasion essayA writing that takes a position for or against something and tries to convince the reader to accept the same view. Also called an argument essay. because you are trying to convince your readers that your argument has merit. In this lesson, you will learn the types of evidence you can use to support your arguments and how to identify and evaluate evidence.

Types of Evidence

You will come across three major types of evidence in your researchThe use of outside sources as well as investigations and observations in order to form ideas and support claims. Also, the information obtained from such efforts.: factsA piece of information that can be proven. Something that is true and indisputable. and statisticsA numerical value that provides information about something., expertSomeone who is very knowledgeable about a topic. opinionPoint of view that shows a personal belief or bias and cannot be proven to be completely true., and anecdotal evidenceA brief, interesting story that supports a claim in a critical analysis or persuasion essay.. You need to understand that not all evidence is considered equally strong. Facts and statistics are considered the strongest type of evidence you can use in support of your arguments, followed by expert opinions. Use anecdotal evidence when facts, statistics, and expert opinion are not available or in conjunction with the other types.

Facts are those things that cannot be argued. An example of a fact is the statement, "It is twenty degrees outside today." It would be twenty degrees no matter who measures the temperature. Compare this with an opinion, such as "the cold weather is miserable." The latter can be disputed; it is not fact that the cold is miserable. Not everyone would agree with that statement, and it is not supported by empirical, scientific evidence.

Statistics are numbers and amounts determined through logical analysis and collection of facts. For example, the U.S. unemployment rate fell from 7.2 percent in September 2013 to 6.6 percent in January 2014.

Remember, as with all support, all facts and statistics that you use as evidence must come from credible sourcesA person, book, article, or other thing that supplies information..

Expert opinion is relied upon a great deal in both the legal and academic worlds. Not only is it considered convincing and reliable evidence in certain kinds of civil and criminal trials, academics often rely upon the opinions of learned professionals in supporting the claimsA statement that something is true, such as the thesis of an essay. A successful writer must present evidence to prove his/her claim. of their papers or presentations.

An example of expert opinion evidence is, "Dr. Bruce Williamson, the country's leading expert in furry black mold research, believes that furry black mold is responsible for a larger amount of all upper respiratory infections in large urban areas than current research suggests."

As with statistical evidence, however, be certain to verify the credibility of your expert opinion evidence. Only use that expert opinion which is deemed accurate and relevant to your argument.

An anecdote is a short story regarding a real-life person or event. Anecdotal evidence differs from facts and statistics and expert opinions in that it is often informally gathered by an individual or group rather than by scientific study or research.

An example of anecdotal evidence is, "I have resided in northern Michigan for thirty years and I can tell you, this winter has been one of the coldest, snowiest, and windiest we've had in over a decade."

While anecdotal evidence is not necessarily grounded in undisputed facts, logical analysis, or learned reasoning, it still possesses persuasive power. Utilizing the personal human experience as a means of relaying information can make your argument more relatable for your reader. Be sure, however, to select anecdotal evidence that is relevant to your argument and grounded in reasonable thought or universal understanding of a situation.

Ask yourself these questions to identify and evaluate credible sources.

In addition to identifying the kinds of evidence that are most relevant and reliable for your writing, you need to consider the sources from which the evidence comes. For example, suppose you want to use a statistical study from an academic journal. Once you have established that the statistics and data themselves appear to be valid and appropriate for your paper, consider the following questions in order to establish the credibility of the source:

This is important to consider because sources that are published by legitimate and recognizable publishers will be considered more reliable and accurate than those put out by unknown publishing houses. As you continue in your chosen field of study, you will learn the trusted publishers in your field. If you are unsure whether a publisher is legitimate, be sure to check with your instructor or a research librarian. Understanding who published the work can also help you to determine if there may be any issues of biasIn writing, bias indicates a writer's personal prejudice for or against an idea, person, activity, or object. Being objective, or displaying no tendency toward a preference, is the opposite of showing bias..

In reviewing the authorship of a source, take into account three factors:

ArticlesA non-fiction, often informative writing that forms a part of a publication, such as a magazine or newspaper. written and studies conducted in the recent past are likely to be more current and more persuasive than those published a long time ago. This will be more important in certain fields like science and technology than in history and literature.

Identifying the intended audience can help you to determine if the article you wish to rely upon is potentially biased. For example, if the article is reviewing the study of a recently approved drug and is written by the pharmaceutical company for physicians, you may want to consider the potential for bias. The data may be skewed or presented in such a way that its intention is to convince physicians to endorse a certain drug rather than setting forth impartial evidence regarding the effectiveness or overall safety of the drug itself.

Authors that have included in-text citationsInformation about a source, such as the author, date, and page number, in an essay or research paper that helps readers find the source in the works cited or references page. There are different rules for how to use in-text citations depending on the context of the citation and the style of formatting you are using. and a works cited pageAn alphabetized list of publication information about the sources used in an MLA-formatted essay or research paper. or references pageAn alphabetized list of publication information about the sources used in an APA-formatted essay or research paper. in their articles (as you yourself will have to provide) likely have an additional layer of credibility, as they have used the published work of others to support their arguments and claims. Depending on the source, this information may take the form of endnotes and footnotes.

You need to make sure that the information your source is using is reliable, as well. This is an issue particularly when the source you wish to use is not peer-reviewedWritings that have been evaluated by experts in a subject before they are published. or published by a known and credible publisher, or where the author is making claims that are perhaps outside the "norm" for that particular field or industry.

This question again gets to the issue of bias. When a source has been funded by an organization, company, or even individual who may have a vested interest in the success of the source or the persuasiveness of the claim, proceed with caution. For instance, a cancer research center funded by cigarette companies may not be the best place to get information on the relationship between smoking and lung cancer.

The writing style can often tell you a great deal about the source of the article. For example, those articles that are formally written are more likely to be from a peer-reviewed journal. Articles written in a more colloquialInformal language. or informal tone are probably from a popular media source and are therefore less suitable as support in an academic essayA short piece of writing that focuses on at least one main idea. Some essays are also focused on the author's unique point of view, making them personal or autobiographical, while others are focused on a particular literary, scientific, or political subject. .

Scholarly, peer-reviewed journals are not the only type of credible source; however, some instructors may request that you limit your sources to such journals. Journals are often more field-specific and are comprised of articles by scholars, academics, and professionals from that field. Journals are comparatively plainer-looking than popular media and contain no advertising. Popular media, on the other hand, often includes advertisements and other visual illustrations or photographs, and is made up of articles and stories that are more news-oriented, journalistic, and opinionated than those found in an academic journalA scholarly periodical that publishes peer-reviewed research in a particular area of study..

Keep in mind that some instructors may require you to use peer-reviewed, scholarly materials as evidentiary sources. In those cases, don't immediately discount non-peer-reviewed materials. While you may not be able to cite those materials or use them as evidentiary support for your thesis, non-peer-reviewed articles can provide you with links to peer-reviewed materials as well as informative background Information that describes the history or circumstances of a topic. information.

Identifying Credible Online Sources

Because a great deal of the research you will find yourself conducting in the process of writing a persuasion essay will be online, you must understand how to identify online sources that are credible. Avoid certain online sources that may be informative and helpful for your overall understanding of a subject but are not appropriate as cited sources for a paperAn academic essay that usually includes research and citations..

One such example is Wikipedia, which is essentially an informal online encyclopedia. While Wikipedia is often credited for its expert contributions and wealth of data, most college instructors will not allow you to use information found on Wikipedia as a source in an academic essay since its materials are difficult to verify in terms of authorship and editing. Instead, use these websites as a starting point for your research. Many will link to reports and peer-reviewed research. Go to the actual source of the information and use that as evidence. To determine whether an online source is credible, ask yourself the following questions:

Online databases can also be a valuable tool in your research. From paid databases that may be available through your school library to free databases such as Google Scholar, you may use the Internet to locate articles you have already identified or to search for more sources to complement those you already have. No matter what the reason, it is important to keep in mind that the reputation or reliability of an online database does not verify the credibility of a source. You must still assess each source's credibility independently.