Skip to Main Content

How to do library research: Critically Evaluate Information

Primary and secondary sources

What is a primary source?

A primary source is original information about an event, person, object, product, or work of art in which there has been no comment or analysis about it; a primary source presents information in its original form, neither interpreted nor condensed nor evaluated by other writers.

Think about it in your own context. What primary sources have you created to tell the story of you? (For example, maybe a tweet, a picture of something you enjoy doing, or your student ID card).


What is a secondary source? 

A secondary source is an interpretation of a primary source. For example, if your professor asks you to view a film and then write a paragraph about it's meaning to you, the film is the primary source, while your analysis of the film is the secondary source. 

Common information source formats

What do we mean by “sources”?

Common types of sources

Where to get them

Why & how to use them


Available in print or as ebooks from your academic library; these are often "monographs" or books that focus closely on a research topic.

SU Libraries’ Quick

See: How to Find Books

Books contain background or historical facts and can be used to frame an analysis or argument.

Hot Tip! Locate only the information you need in books by skimming chapter titles or by finding keywords in the Index located at the end.


‚ÄčArticles are published within newspapers, magazines, and scholarly journals on a daily, weekly, monthly, or quarterly basis.

Go to SU Libraries home page, Find Articles A-Z Databases or by Subject.

See: How to Find Articles

Because they are published more frequently than books, articles can contain the most up-to-date information on a topic. Information found in scholarly journal articles  can be used to support specific aspects of your analysis or argument.


Any information made public on the open web.

Search engines on the open web such as Google

See Critically Evaluating Sources above.

Although you should generally begin research using the SU Libraries’ resources, you may need to find additional sources using popular search engines like Google. Information from the open web can be created by anyone, so it’s important to critically evaluate any sources you might consider for use in academic work.

Critically Evaluate Information

Critically Evaluating Sources (what do we mean by "sources"?)

For college-level research, you'll want to consider using only the highest-quality information sources that you can find. Between the internet and SU’s library, the “best” information can depend on the assignment. Here are some ways to determine the best information sources to lend support to your own research.

Use the C.R.A.P. method to evaluate information that you may consider using: (Currency, Relevance, Author expertise, and Purpose)


Consider each

Why is this important?

Is the source Current?

  • When was the source published?
  • If it’s a website, when was it last updated?
  • Does your topic require current information or more historical resources?
  • Can you find even more current sources than this one?

Check your research assignment directions. Some majors/disciplines require students to use only the most current scholarship in the field, while current scholarship is not important for others.

In the sciences, the most up-to-date research is often considered the most valuable. For example, a research study about new technology from ten years ago might be less important than a study conducted last year.

Is the source Relevant?

  • Does the source support your argument/idea/question?
  • Does the source meet your assignment requirements?
  • Is the information too technical or too simplified for you to use?

Every single source that shows up in your work should be there for a reason and your reader should not have to guess what that reason is.

Every source that you include in your research work should be there to strengthen your idea or argument.

Is the Author an expert?

  • Authors of the source should be experts in some way. If you must use a scholarly source, an expert authority on the subject will have an advanced degree such as a PhD.
  • Is the author affiliated with a prominent organization or educational institution?
  • Can you find information about the author from reference sources or the internet? 

Consider an author’s credentials before you commit to using the information that they have made public. Experts often have advanced academic degrees, institutional affiliations, and long track records of publishing articles and books containing earlier research. Find author information:

In books – About the Author page

In articles from a database – the article citation or the article itself.

Website – See Evaluating Web Sources below

What is the source’s Purpose?

  • Is the author’s purpose to sell, persuade, entertain, or inform?
  • Is there an obvious bias or prejudice?
  • Are alternative points of view presented?
    Does the author omit important facts or data that might disprove the claim?
  • Does the author use strong or emotional language?

 An author’s bias can affect the validity or even the truthfulness of the information they have made public, treating one side of an issue more favorably than another. For example, an Apple website will claim its iPhone is the best in the world. Motorola will claim its Droid is the best. They both make this claim because they want to sell their phones.

Consumer Reports, an un-biased group who rates products, will study both phones and determine superiority based on what consumers desire and they make that viewpoint known to readers.

Using biased sources to support your ideas makes it easy for your audience to challenge the validity of your argument or analysis.







Uses of different types of sources


Bean, J. C. (2011). Designing and sequencing assignments to teach undergraduate research. In Engaging ideas: The professor's guide to integrating writing, critical thinking, and active learning in the classroom (2nd ed., p. 239). San Francisco: Jossey-Bass.


This information is an adaptation of Evaluating Information – Applying the CRAAP Test created by Meriam Library, CSU, Chico