What is a question you should ask to evaluate the credibility of a source?

It depends on what you are looking for, but in general, you should ask yourself many questions:

• Is this a site that I can trust?
• Who wrote this?
• Is the author someone I can trust?
• Can I confirm this information anywhere else?
• Does this information seem biased?

If it is basic fact information, for instance, make sure you check the dictionary or an encyclopedia over someone's personal blog. It doesn't mean that the blog is bad or that that person might not have any additional information, but checking all the facts that you can is always a good idea.

If it is information that not a lot of people know, you might have to go with some information that you aren't sure of. In that case, you might want to read other entries on the blog, or the comments, to see if other people had success following this person's advice, or if the person seems to have the sort of experience they need in order to correctly answer your question.