9.2 Types of Sources

When you find sources in your research, you will need to be able to distinguish which types of sources they will be categorized as when they appear in your research essay. These types are not always obvious or apparent, nor are they exclusive (a single source can be of several types simultaneously), but confusing them can cause problems with how you involve their ideas and information in your essay, and that can hurt your grade and harm your credibility as a writer. In other words, your professor will be able to see and distinguish the types of sources you are using in your research essay, so it is vital that you can too.

Types of Sources: Primary, Secondary, and Tertiary

Writers classify research resources into three categories: primary sources, secondary sources, and tertiary sources. These three types can come in any form: Websites, magazines, books, news stories, etc. What distinguishes them is not the publication category but instead how relevant they are to your subject and purpose.

“Primary, Secondary, & Tertiary Sources” by sccclibrary

Primary sources are direct, sources of information or ideas. They are generally the best sources to use in research essays. Primary research is information that has not yet been critiqued, interpreted, or analyzed by a second (or third, etc) party.

Primary sources are texts that arise directly from a particular event or time. They may be letters, speeches, works of art, works of literature, diaries, direct personal observations, newspaper articles that offer direct observations of current events, survey responses, tweets, other social media posts, original scholarly research (meaning research that the author or authors conduct themselves) or any other content that comes out of direct involvement with an event or a research study.

But whether a source is primary relies on your subject and purpose. For example, if you’re writing about free speech in the Constitution, then the First Amendment to the Constitution is your primary source. A Wikipedia entry about the First Amendment would not be a primary source. But this would change if your subject or purpose changed, so if you were writing an essay about how Wikipedia’s entry influences what people think free speech is, then Wikipedia is now your primary source.

Primary sources can be popular (if published in newspapers, magazines or websites for the general public) or academic (if written by scholars and published in scholarly journals).

The following types often end up being primary sources:

• Research articles
• Literary texts
• Poems, paintings, sculptures, songs, or other works of art
• Historical documents such as diaries or letters
• Autobiographies or other personal accounts
• Scholarly journal articles in which the author(s) discuss the methods and results from their own original research/experiments
• Blog posts
• Speeches
• Data from surveys or polls
• Photos, videos, sound recordings
• Interviews or transcripts
• Government documents (such as reports of legislative sessions, laws or court decisions, financial or economic reports, and more)
• Newspaper and Magazine articles that report directly on current events (although these can also be considered Secondary)
• Investigative journalism (sometimes considered Secondary as well)

Secondary sources are in-depth analyses of, interpretations of, and discussions about primary sources. Secondary sources summarize, interpret, critique, analyze, or offer commentary on primary sources. They are often useful and insightful supplements to include in research essays, for they can help you and your audience contextualize and make clear sense of primary sources.

In a secondary source, an author’s subject is not necessarily something that he or she directly experienced. The author of a secondary source may be summarizing, interpreting, or analyzing data or information from someone else’s research or offering an interpretation or opinion on current events. Thus, the secondary source is one step away from the original, primary topic/subject/research study.

For example, if you’re writing about the First Amendment, you might read articles about legal cases that involved First Amendment rights, or editorials expressing commentary on the First Amendment. These sources would be considered secondary sources because they are one step removed from the primary source of information.

Secondary sources can be popular (if published in newspapers, magazines or websites for the general public) or academic (if written by scholars and published in scholarly journals).

The following types often end up being secondary sources:

• Biographical books
• Television documentaries
• Literary and scientific reviews
• Book, movie, or art reviews
• Summaries of the findings from other people’s research
• Interpretations or analyses of primary source materials or other people’s research
• Histories or biographies
• Political commentary
• Newspaper and Magazine articles that mainly synthesize others’ research or primary materials (remember, newspaper and magazine articles can also be considered primary, depending on the content)

Tertiary sources are less-engaged summaries or surveys of secondary or primary sources. These can be helpful guides when you are beginning your research, but they are rarely good sources to use in research essays.

Tertiary sources are syntheses of primary and secondary sources. The person/people who compose a tertiary text are summarizing, compiling, and/or paraphrasing others’ work. These sources sometimes do not even list an author. Often you would want to use a tertiary source to find both Primary and Secondary sources. Keep in mind that, too, that it may sometimes be difficult to categorize something as strictly tertiary, and that it may depend on how you decide to use the item in your research and writing. Your instructors will often not accept the sole use of tertiary sources for your papers. Instead, you should strive to only use tertiary sources to find more academic sources, as they often have titles of other works and links (f they are web-based) to more academic primary and secondary sources that you can use instead.

For example, if you’re writing about the First Amendment, then you might read a Wikipedia page on it, or a textbook section explaining it. These would be tertiary sources. They are helpful for teaching you the basics of a subject, and for finding out what the primary and secondary sources are for it, but tertiary sources are generally weak as sources themselves.

Tertiary sources can be popular or academic depending on the content and publisher.

The following types often end up being tertiary sources:

• Encyclopedias
• Course textbooks
• News articles
• Introductory or how-to Websites or videos
• Dictionaries
• Guides
• Wikipedia

Keep in mind that your subject and purpose determine the kinds of primary and secondary sources you should seek and use in your essay. If you are writing a research essay about reality television shows, you will need to use some reality shows as a primary source, but secondary sources, such as a reviewer’s critique, are also important. If you are writing about the health effects of nicotine, you will probably want to read the published results of scientific studies, but secondary sources, such as magazine articles discussing the outcome of a recent study, may also be helpful.

Types of Publications: Scholarly, Trade, and Popular

In your research, you will encounter three very different types of publications: scholarly (including peer-reviewed), trade, and popular. Because all three types can cover the same subjects, they can sometimes seem similar to those new to research, but is important that you learn to distinguish between them. These types can appear on Websites, databases, or in print.

“Scholarly and Popular Sources” by Carnegie Vincent Library is licensed under CC BY

Scholarly publications (sometimes called academic publications) present reports and articles written by experts in academic or scientific fields. When you hear of scientists reporting new results or discoveries, or research teams finding new correlations or statistics, or scholars presenting important theories or analyses, that is because these are published in scholarly journals.

• Audience: other experts, scholars, and academics; also student researchers
• Content: long articles, lots of detailed information, many complex charts and graphs
• Style: highly technical and academic, neutral and objective, information-heavy
• Appearance: plain and serious
• Citation: numerous citations, long bibliographies, many footnotes

Peer-reviewed publications are a special type of scholarly publication. They go through a long, difficult process of being evaluated by other experts and scholars in the field before they are even published. In other words, the expert authors must present their articles and reports to other experts—their peers—and get their approval first. That approval typically focuses on the legitimacy, reliability, and accuracy of the methods, sources, and theories used in the writing. Once this review by peers is complete, it can be published, and this peer-reviewed publication is therefore the most reliable type of publication that exists.

All peer-reviewed publications are scholarly, but not all scholarly publications are peer-reviewed. Both types are good sources to use in research essays, but peer-reviewed will generally be the best.

Because scholarly articles tend to be so long and detailed, they can be difficult to skim in order to find out whether they might be useful for your research. This is why they often contain abstracts.

Abstracts are short summaries of long scholarly articles or reports. These summaries are normally about one paragraph in length, and they explain what the article or report covers, what its methods or sources are, what its findings are, and what the authors’ conclusions are. Abstracts are found at the beginning of the article, and sometimes in the database information for the article. The whole purpose of abstracts is to make research easier on you by letting you know right away what the article or report contains.

Trade publications present articles, reports, and trends written by professionals in industries or business and technical fields, or by professional writers with experience and knowledge of the trade. When engineers learn about new technology to purchase and use, or physicians learn about drugs to prescribe, or business owners learn new methods to employ, they do so by reading trade publications.

• Audience: other professionals within the industry or field; also experienced clients and consumers
• Content: medium-length articles, news, illustrations, photos, and advertisements related to the trade, industry, or field
• Style: commercial, persuasive with some professional objectivity, specialized in its terminology and jargon
• Appearance: vivid and state-of-the-art
• Citation: some footnotes and bibliographies of sources

Trade publications can be useful for many types of research essays, but you will need to evaluate them closely since they can include biased information in attempts to sell or promote for profit.

Popular publications present articles, news, and opinions written by journalists and freelance writers. Most of the magazines, journals, and news sources you encounter daily, such as The New York Times, Time Magazine, USA Today, and The Wallstreet Journal, are popular publications.

• Audience: general, everyday readers
• Content: short- and medium-length articles, information tidbits, news, illustrations and photos, advertisements about common products and services
• Style: entertaining, persuasive, commercial, accessible, sometimes provocative and controversial
• Appearance: glossy and stylized
• Citation: very few official citations, sometimes brief references within articles

Popular publications can be useful sources for examples in research essays, but they are not typically strong as sources for important information or ideas. They can often demonstrate what the common consensus or controversy on an issue is, and they can help point you toward better secondary and primary sources. But they will need to be evaluated very carefully, for they are almost always biased in selecting what kind of information to present, and how.

Terminology for Publication Forms

• Book: a general term for a long work of any genre, often 50,000 words or more
• Novel: a fiction book, which means the ideas and events it contains were imagined for entertainment or literary purposes
• Story: a short work of fiction, often less than 10,000 words
• News story: a short report for the general public of real, current events
• Essay or article: a short work of non-fiction, often less than 10,000 words
• Textbook: a non-fiction book used to teach you something, often including summaries, glossaries, comprehension questions, and other study aids
• Journal, review, or magazine: a collection of articles and essays, or of stories, often one that recurs every so often as issues
• Periodical: a collection of articles or essays that comes out regularly, such as a newspaper or magazine
• Reference book: a non-fiction book that presents information collected in lists or entries, such as a dictionary or encyclopedia
• Op-Ed or opinion piece: an argumentative or opinionated article often published within news sites or journals, as opposed to purely informative reports or articles. These are not the same as unreliable sources that are secretly biased, fake, etc.; instead, these are openly clarified as debatable positions and arguments and are thus legitimate in that they are what they say they are.
• Literature or literary works: writings that are intended to be artful, often fiction, but can be in the form of poems, plays, scripts, and songs
• Biography: non-fiction about a person’s life
• Autobiography: non-fiction about the author’s own life
• Anthology: a collection of writings, often of literary works

Now that you know what kinds of sources exist, it is important to remember that various disciplines find certain types of evidence to be more acceptable and appropriate than others. For instance, while the Humanities may consider anything from passages of text to art appropriate evidence, certain sciences may prefer data and statistics. What is most important to remember, no matter the discipline for which you are writing and pulling evidence, is that the evidence is never enough by itself. You must always be sure to explain why, and how, that evidence supports your claims or ideas. For more information on types of evidence considered appropriate for each academic discipline.