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University of Portland Clark Library

CST 107: Public Speaking for Change: Levels of Evidence

Levels of Evidence Pyramid


  • Motivation for publishing
  • Publication process
  • What sources does the author cite?
  • Can you corroborate the evidence?

Evidence pyramid with opinion pieces at bottom, followed by newspapers/encyclopedia articles, followed by books, followed by scholarly journal articles.

Text of the pyramid above for web accessibility (from top-to-bottom):

Scholarly Journal Articles

Academic Books

Newspapers, Magazines, Encyclopedia Articles

Opinion: Advocacy websites, blog posts, tweets, etc. Editorials/Letters to the Editor

Levels of Bias and Quality in News Sources

The best-known chart of left-right perspective vs. credibility is the Media Bias Chart below; another is the Media Ideology Map currently in development, which will present media perspectives on issues rather than a global rating. Read a guide to the MIM developer's methodology.

The Media Bias Chart

Select this screen capture of the Media Bias Chart to go to an interactive version.

View a list of news sources covered in the Media Bias Chart.
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