[ame=http://en.wikipedia.org/wiki/Bias]Bias - Wikipedia, the free encyclopedia[/ame]
[ame=http://en.wikipedia.org/wiki/Fact_checker]Fact checker - Wikipedia, the free encyclopedia[/ame]
Fact-checking involves researching original sources when possible to determine that the material was used accurately and presented in context. In publishing terms, it means verifying quotes with sources. In user terms, it means reading multiple sources of data and checking footnotes/endnotes listed in the article.
Source bias means determining how data was collected, whether the methodology was scientific, and whether the data is presented accurately, without being tainted by an individual's opinions.
These days, most American newspapers don't employ fact-checkers anymore, which means users need to exercise caution.