From AdFontes Media.

If you never disagree with the slant of your news source, then you probably aren’t reading a balanced news source; you’re just reading a source aligned with your bias.

A truly informed person will consult credible sources (above the green line) on both the left and right. Know where your biases are, and make an effort to read credible, fact-based news and analysis that presents views that differ from your own.