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Evaluating Sources

Source Types

When starting research for a paper or other project, it is important for you to be able to identify the types of sources you discover. You may need to use specific source types based on the instructions your professor provides, and some some source types may not be appropriate for your project. In addition, recognizing a source type will help you determine what kind of information you are likely to gain from the source and may help you estimate how much time you will need to spend reading a source. You also need to know the source type so that you can cite the source correctly in whatever style your professor requires. 

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Source Type by Intended Readership
Source Type by Author Perspective
Source Type by Publication Type

Source Type by Intended Readership
Research at the university level is often divided into “scholarly vs. popular” camps, but in fact differences among sources are more nuanced than that. Although scholarly works will certainly make up a large percentage of most academic research topics, material that is tagged as a “scholarly” may not be the only type of information you need, and sometimes scholarly material may not even be the best venue for answering your question. Sources can be better categorized as follows:

  • Scholarly Sources are produced to inform and explore ideas related to academic disciplines. They are written by subject experts, usually people with PhDs or other terminal academic degrees in the field they are writing about and will provide comprehensive bibliographies. Scholarly sources are reviewed by other experts with similar credentials for quality, validity, and originality prior to publication. Scholarly sources do not rely on advertising and are usually only available through academic institutions.
  • Non-scholarly Sources may be written by subject experts, professional authors, or amateur authors. They are typically written for a general audience seeking to learn more about a topic without the academic lingo and they can be fairly easily obtained, though at a per-issue or subscription cost. Non-scholarly sources should not be automatically discounted. Non-scholarly sources rely on advertising, some may include poorly written information or misinformation, and most contain opinion of varying quality, but respected non-scholarly publications such as Time and Nature can provide excellent introductions to a topic and may explain current thinking on issues such as the economy or healthcare. Non-scholarly sources to avoid are those that do not cite their sources in any way. 
  • News Sources provide daily or weekly descriptions of current events. Larger news outlets may contain opinion pieces and in-depth reporting, which you should ensure is backed by research before using in a research project. Most news sources are only partially free to access and rely on advertising. Of course, not everything with "news" in the title is a valid source of news. Always read the "About" section of online news sources and search the Internet to find the political bias of the news outlet if it is not obvious.
  • Grey Literature is information produced outside formal publishing channels but can nonetheless provide valuable data. It is often free to access. Examples of grey literature include government reports, policy papers, conference proceedings, reports from non-governmental organizations, trade publications, geological surveys, fact sheets, dissertations, pre-prints of scholarly articles, and maps.

Source Type by Author Perspective
With any research project, you must consider the perspective of your sources. A source may be primary, secondary, or tertiary. 

Primary Sources
The definition of "primary source" differs depending on the discipline you are studying.

  • In the humanities (subjects such as art, English, religion, and philosophy) and the social sciences (subjects such as anthropology, history, political science, sociology), primary sources are generally defined as material produced at the time of an event, or by a person significantly involved with an event or who lived during a time period being studied and is recalling that time period. Primary sources in the humanities and social sciences can take many forms, including:
    • personal and professional correspondence
    • professional papers
    • diaries
    • memoirs
    • manuscripts
    • constitutions, treaties, pacts and other political documents
    • photographs
    • works of art and literature
    • artifacts and other objects
    • letters
    • speeches
    • autobiographies
    • oral histories
    • interviews
    • creative works such as films, poetry, music, or art, and artifacts
       

  • In the sciences, a primary source is a report on the results of an experiment by the person or group who performed it. They are usually published as scientific articles that present original data. In a primary research article, you will see most or all of the following elements clearly presented:

    • An abstract/summary of the research about to be presented
    • Author’s affiliation
    • Introduction with thesis statement
    • A review of other literature pertaining to the experiment
    • Methods used to conduct the experiment
    • Materials and equipment used in the experiment
    • Results of the experiment (data) - may include tables, charts, graphs, figures, photographs
    • Discussion of the results
    • Conclusion
    • References or bibliography

Primary sources can be found in many different formats. They may stand alone as individual documents in their original forms or be copied/reproduced and collected by theme or topic in books or databases. Some have been digitized and are available for free on the Internet. Many are digitized and available only by accessing databases provided and paid for by your library. Many exist only in their original formats and are still held exclusively by the library, archive, museum, or individual that owns them. Sometimes primary sources that haven't been digitized are available to be used by the general public and sometimes use is restricted only to professional researchers. 

Depending on when they were written, newspapers and magazine/journal articles may be considered primary sources. For example, a New York Times article written in 1865 may be considered a primary document when one is studying the U.S. Civil War.

Secondary Sources
A secondary source is a document which is derived from, or based on, study and analysis of primary sources. These are works that are not original manuscripts or contemporary records, but which critique, comment on, or build upon these primary sources. They interpret, analyze, and/or evaluate primary sources (and other secondary sources) and provide the context necessary to understand primary sources.

Secondary sources often come in the form of books and articles. They may be printed or electronic material and can include:

  • reviews
  • studies
  • analyses
  • reports
  • criticism
  • histories
  • commentaries

Tertiary Sources
A tertiary source is often called a reference work. Tertiary sources compile, summarize, digest, and organize the information in primary and secondary sources to provide background information on a topic. Tertiary sources are typically consulted for fact checking only and are not used as cited evidence in papers written for university level courses.

Examples of tertiary sources are:

  • almanacs
  • dictionaries
  • digests
  • encyclopedias (including Wikipedia)
  • guidebooks
  • manuals
  • textbooks

Primary, secondary, and tertiary sources are not always easy to isolate during database searching. Primary, secondary, and tertiary sources may co-exist in a given database, and many databases do not identify source types as part of the metadata. However, some databases contain only primary source material, some contain only secondary source material, and some contain only tertiary source material. It is important to read the descriptions of databases before you begin searching them so that you know what to expect. You can learn more about how to select databases on our Databases List guide.

Source Type by Publication Type

For academic research, you will most often be required to use books or articles, but you may also have the need for book chapters, newspapers, media, reports, or other types of sources.

You can easily figure out what type of source you are looking by examining the item’s citation information, as long as you are familiar with the elements of a citation.

Book Citation
Normally includes the author or authors, date of publication, the title and subtitle of the book, and the publisher. 

Sapolsky, R. M. (2017). Behave: The biology of humans at our best and worst. Penguin Books.

Book Chapter Citation
Some scholarly books are made up of individual chapters written by different authors. This is known as an edited work, or sometimes an anthology. In that case, an editor is responsible for putting the book together. A book chapter citation includes the author(s) of the chapter, the title of the chapter, the year of publication, the book's editor(s), the book's title and subtitle, the pages on which the chapter appears, and the publisher. 

Aron, L., Botella, M., & Lubart, T. (2019). Culinary arts: Talent and their development. In R. F. Subotnik, P. Olszewski-Kubilius, & F. C. Worrell
      (Eds.), The psychology of high performance: Developing human potential into domain-specific talent (pp. 345–359). American Psychological
      Association.

Journal or Magazine Article Citation
An article citation includes the author(s), date of the article's publication (sometimes including a month), title of the article, the title of the journal in which the article was published, the journal’s volume and issue numbers, and the page numbers of the journal on which the article appeared. If a digital object identifier (DOI) code is available, that should also be included.

Grady, J. S., Her, M., Moreno, G., Perez, C., & Yelinek, J. (2019). Emotions in storybooks: A comparison of storybooks that represent ethnic
     and racial groups in the United States. Psychology of Popular Media Culture, 8(3), 207–217. https://doi.org/10.1037/ppm0000185

Book Reviews
Book reviews can frequently be mistaken for research articles since they are usually published in journals and discoverable in many databases. When you are trying to decide whether a book might be helpful to your research, a review can be quite valuable. However, it is important that you do not use book reviews as evidence in a research project. The book itself is what should inform your project and appear in a bibliography. You use the review merely to decide whether the book is worth taking the time to read. 

A book review will normally be tagged as such in the database record if not the title of the review. Another clue that an item is a review is that the author of the book being reviewed does not appear in the author field of the review's record. In this example, Sands is the author of the book review. (Rebecca Skloot is the author of the book, The Immortal Life of Henrietta Lacks.)

Newspaper Article Citation
The most recognizable indicator of a newspaper article is the full date with exact day, as opposed to merely a year with a month. Additionally, the page numbers may include a section title or number. If the article is from a news website (e.g., CNN, HuffPost) that does not have an associated daily or weekly print newspaper, the format may resemble a webpage citation.

Newspaper article citations include the name of the author(s), full date, title of article, title of newspaper, section and/or page numbers, and URL if applicable, 

Carey, B. (2019, March 22). Can we get better at forgetting? The New York Times.
     https://www.nytimes.com/2019/03/22/health/memory-forgetting-psychology.html

Webpage Citation
A webpage citation contains the basic elements of other citations, including the author of the page content (which may be attributed to an organization rather than an individual, the date of publication, the title of the page, and the URL (web address), which is the main indicator that the source is a webpage. 

World Health Organization. (2018, May 24). The top 10 causes of death.
     https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death

There are many more types of sources you may encounter while researching. Ask a Librarian if you are uncertain about the types of sources you discover while searching, and if they are appropriate to use in research projects.