The Continuum of Credibility is a tool to help you determine how closely you need to consider a source to determine if it is appropriate for use in an academic paper based on where it is published.
*Pro Tip: Just as with your own writing, audience is critical to evaluation. When a noted expert is authoring a newspaper or magazine article, they are anticipating a popular audience and write accordingly. So even though you may have the most brilliant thinker of all-time on your topic writing a piece, it is only "scholarly" if their audience is other scholars.