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Principles of Citing Sources: Appraising and Choosing Sources

At a Glance

  • It can be difficult to distinguish between a scholarly source and a popular one. In general, scholarly sources have been approved by a group with recognized expertise in the field under discussion. All other sources can be generally described as popular sources.
  • While writing, there are times you might rely on popular sources and times where scholarly sources may be better to cite.
  • What qualifies as evidence or as a reliable source varies across different disciplines, and sometimes among different courses in the same discipline. It’s very important to check with your teachers about appropriate sources for the research you’ve been assigned.

On This Page

Scholarly vs. Popular Sources

There are two types of sources that you can cite: scholarly sources and popular sources.

  1. Scholarly sources: Scholarly sources are those that have been approved by a group with recognized expertise in the field under discussion. Books published by university presses fall into this category, as do articles published in peer-reviewed journals—journals where the editors send pieces out to be read by experts in the field before deciding to publish them. The Yale library subscribes to several databases that specialize in scholarly sources (such as Academic Search Premier). If you use sources for facts or ideas in your writing, some research projects will demand that you rely heavily, if not exclusively, on scholarly sources. Scholarly sources are not infallible, but their publication process includes many steps for verifying facts, for reducing political bias, and for identifying conflicts of interest (for instance, informing readers when a drug company has funded research on its own product).
  2. Popular sources: In a narrow sense, every other source that cannot be classified as scholarly could be called a popular source. But this does not mean that all popular sources are of equal reliability. Nor does it mean that you should use only scholarly sources for all of your writing at Yale. Depending on the research context, some projects will permit a mix of scholarly and popular sources. For example, in a history seminar about World War II, you would usually be expected to consult the most definitive, academic studies of the period. But in a literary essay analyzing Joseph Heller’s Catch-22, you may be able to rely on popular history sources for facts about World War II because the focus of your paper is on interpreting the novel.
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To understand this difference, it may help to recognize that when you write for a departmental class, you are writing for an audience more expert than the common reader. When writing about Republican and Democratic voting patterns on stem cell research, science reports from a general interest magazine like Newsweek might be considered sufficiently authoritative. But when you write about stem cells for a Biomedical Engineering class, your teachers and classmates are considered more expert than the average non-scientist reader. For this audience, your sources must have stronger science credentials and must generally be working scientists, not journalists.

Classifying Journalistic and Online Sources

Newspapers are not as easy to classify as other sources. Newspapers are not scholarly sources, but some would not properly be termed popular, either. Every source must be questioned for its stake in the material. The New York Post is notoriously inflammatory, for instance, and also seems to love television shows broadcast on the Fox network (owned by the same company). But some newspapers, such as The Wall Street Journal and The New York Times, have developed a national or even worldwide reputation for thoroughness. On issues of fact, major mainstream magazines such as Newsweek and Time are also generally reliable.

Finally, it’s worth noting that many Internet sources are less reliable than print sources. Because it’s relatively inexpensive to put material on the Web (when compared to the cost of print publication), it’s easy for private individuals to post their unverified opinions on websites. It’s also cost-effective for corporations or other organizations to post websites that appear to be factual but actually serve to promote the group’s agenda. Not all Internet sources are unreliable, and some unreliable sources—when used carefully—can serve a role in research (see “Sources of Opinion” below). But you should take special care when doing research on the Internet.

Using Sources as Objects of Analysis

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Any source can be cited if it’s being used as what we might call an “object” source—for instance, if the text is an object of analysis, such as the poem in a literary criticism paper. In these instances, you are not relying on the source for authoritative information about a topic, but are instead investigating the source itself and using paraphrase and quotation to argue about the source’s meaning. Sources that serve as a project’s obect of analysis can also be called primary sources. Depending on the course, academic papers might use movies, commercials, buildings, magazine advertisements, popular songs, or dialogue recorded on a city bus as their primary source. It’s still necessary to identify the origin of your source, but if your paper makes clear that you do not accept the text as a source of fact but are instead developing your own ideas about the text and how it works, you can profitably use almost anything in an essay. Essays or other works that discuss and analyze a primary source are called secondary sources. Often, papers written for a class will cite only one or two primary sources and multiple secondary sources. 

Assessing the Reliability of Sources of Opinion

Depending on the research context, you may have sources that are not as reliable as scholarly sources but that still add texture or authority to your argument. In the humanities, for instance, critics’ opinions often demonstrate bias (even celebrate it). But because of their authors’ professional experience, such opinions can be used as ideas to extend your own analysis—or to serve as counter-arguments that clarify your own claims. When critics highlight the same element of the text that you focus on, for instance (the ending of a play, the entrance to a building, the color scheme in a movie), their attention can serve as evidence that the component is significant, even as you use your paper to argue for a different interpretation. See Why Cite? for more discussion of counter-argument. Some magazines—like Discover—are more authoritative than a general news magazine but less authoritative than a scholarly journal. In the sciences, studies done by interested parties would normally not be accepted uncritically (such as pollution studies commissioned by chemical companies). But they may still identify key elements of the topic that require attention.

Finally, almost any source can be used as evidence that someone believes the idea you quote. Although that may seem self-evident, such evidence can be surprisingly helpful when developing an argument, especially for articulating the research problem of your essay. If the Harvard Crimson publishes a negative article about Yale’s football team, you probably can’t trust that it’s an unbiased assessment. But such an article can still be cited as evidence that “some people have negative opinions about Yale football.” It can also be cited as evidence that “Football matters enough at some Ivy schools to merit coverage in the campus newspaper.” If you compare it to other articles in the issue that describe cross-campus cooperation, then the football article might be used to suggest “Feelings are divided at Harvard about its rivalry with Yale.” In the sciences and social sciences, you might discuss popular, non-expert representations of a key issue, explaining where they go astray—and therefore why your paper is necessary.