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M E 324: Manufacturing Engineering

Guide to using library resources for students enrolled in ME324: Manufacturing Engineering.

Evaluating Information Sources

Use critical thinking to decide when information is useful, trustworthy, and relevant.

Not all information is created equal

Searching and locating information sources is only one part of the research process. An equally important part is being able to tell if the sources you've located are trustworthy, appropriate, and authoritative.

Sliding Scales

Think of source evaluation as a sliding scale: not as black / white, good / bad. While there are some sources a majority will agree are "good" or "bad" most information falls somewhere in between these two extremes and it's up to YOU to make a final decision.

How Much You Can Trust a Bearded Man?
A silly example of a sliding scale, The Trustworthiness of Beards by Matt McInerney. Click to enlarge.

How you use information will determine if it is "good" or "bad." For example, I may share a BuzzFeed article with my friends but I wouldn't cite it in a research paper.

Evaluating Sources with the C.R.A.P. Test

The CRAP Test asks you to evaluate information sources across four dimensions: Currency, Reliability, Authority, and Purpose. Below each dimension are some questions to ask about your source as you evaluate it. At the bottom of the page you'll find links that explain some of these concepts in more detail.


Is the source up-to date?

  • How current is the information? Is it outdated or likely to be out of date?
  • How old are the references/citations? Are they outdated?
  • Is it current enough for your topic and project?


Is the source accurate?

  • What kind of information is it?
    • Is it a primary or secondary source?
    • Is it a popular or scholarly source?
  • Is the content balanced or biased?
  • Are there references or citations?
    • Are the citations reliable?
    • Are they current?
  • Was it peer reviewed?


Is the author trustworthy?

  • Who wrote or created it? (persons or organization)
  • What are their credentials?
    • Education
    • Employer
    • Professional affiliation
    • Experience
    • Etc.
  • Who is the publisher/sponsor/host?
    • Are they reputable?
    • What kinds of things do they publish? (scholarly, news, entertainment, etc.)


Why was it created?

  • To teach, educate, or inform?
  • To persuade?
  • To sell or promote?
  • To argue a side?
  • To entertain?

Adapted from the original CRAP test.

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Erin Thomas
150 Parks Library
Iowa State University
515 294-9886