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English 110, 120, 122 Communication Skills: Writing: Evaluating Sources

Evaluating Your Sources

Primary sources 

  • According to the Library of Congress "primary sources are the raw materials of history - original documents and objects which were created at the time under study." They are the "actual records that have survived from the past, such as letters, photographs, articles of clothing."

Secondary Sources

  • According to Princeton University, "a secondary source interprets and analyzes primary sources. These sources are one or more steps removed from the event." They encompass and either interpret or explain primary data and artifacts.
    Note: Peer-reviewed publications generally fall into this category.

Tertiary Sources

  • According to BMCC, "Tertiary sources consist of information which is a distillation and collection of primary and secondary sources."  Items such as synopsies, indexes, bibliographies and almanacs generally fall into this category.

Primary sources are original sources of information on which other research is based, including documents such as poems, diaries, court records, interviews, surveys, and fieldwork. Primary materials also include research results generated by experiments, which are published as journal articles in some fields of study and sets of data, such as census statistics which have been tabulated, but not interpreted.

Secondary sources describe or analyze the primary sources. Examples of secondary sources include: dictionaries, encyclopedias, textbooks, and books and articles that interpret or review research works.

Tertiary sources list, compile, digest or index primary or secondary sources. Examples of tertiary resources include indexes, handbooks, digests and almanacs.

If you think about the publication details of the information and consider the following, you will often find your answer:

  • Timing of the event recorded -- If the article was composed close to the time of the event recorded, chances are it is primary material. For instance, a letter written by a soldier during the Vietnam War is primary material, as is an article written in the newspaper or a soldier's letter home during the Civil War. However, an article written analyzing the results of the battle at Gettysburg is secondary material.
  • Rhetorical aim of the written item -- Often, an item that is written with a persuasive, or analytical aim is secondary material. These materials have digested and interpreted the event, rather than reported on it.
  • Context of the researching scholar -- Primary materials for a critic studying the literature of the Civil War are different from primary materials for a historian studying Civil War prisons. The critic's primary materials are the poems, stories, and films of the era. The research scientist's primary materials would be the diaries and writings of slave families.

            *adapted from University of Wisconsin-Stevens Point University Library

Regardless of the type of resource you are examining, always evaluate the accuracy and reliability of the information you find before using it for your research. Use the acronym CARDS to help you do that evaluating. Consider the following when determining the quality of an article or source:

Use C.A.R.D.S.


C - Credibility:

  • Is the author, publisher, or sponsor of the information evident? What are their credentials, reputation, education or affiliations? 

  • Is there an "About Us" or "Contact Us" link?  Besides an email address, is there a phone number or postal address to contact for more information?

  • If it's a book or article, is the author reputable? Does the reference have a bibliography?Is the information still valid today?

A - Accuracy:

  • Do you see errors on the page (spelling, grammar, facts)? Errors like these not only indicate a lack of quality control, but can actually produce inaccuracies in information.

  • Do they cite the sources of their information? 

R - Reliability:

  • Is the source objective or does it advocate a certain point of view?  Use objective sources first, but consider using those advocating different points of view as well.

  • Is the information free of advertising or clearly separated from it?

D - Date:

  • Can you find the copyright date?

  • Are there dates for when it was written or when it was last revised?

  • Do any statistics, graphs, or charts clearly state when the data was collected?

  • Are there links which no longer work?

S - Source:

  • Is the information based on primary or secondary sources? 

  • Are there links to other sources that would score high in this C.A.R.D.S. evaluation?

You can always consult with a librarian at the Research Desk.


If you do nothing else, check the author. The first step to credibility is a name brand. If there is no author, or your author doesn't come up as the author of anything else, the article is probably not credible. If you can't trust the writer, you can't trust what s/he wrote.



Note the internet address domain, e.g. "climate change" site:gov.

Is it a university site? a U.S. government site? an organization's site?

  • .com (commercial or business)

  • .edu (educational institution)

  • .gov(government agency)

  • .mil (military organization)

  • .net (network resource)

  • .org (organization)

You can search for web pages from a particular domain, such as in the search "climate change" site:gov or clean water site:org