what makes one source more credible than another?

Question

Facts
Verifyible data
Peer reviews
Accurate observations
Concsise statements
In other words, a source needs to be able to stand up to skeptical analysis. Sometimes it's impossible to provide a reliable source. This leaves the door open to speculation.

Lance is right. All the things he lists are criteria for reliability in sources, including the idea that it's not always possible to absolutely prove reliability.

Here is a website that discusses how to determine reliability in websites:
http://www.sou.edu/library/searchtools/evaluate.html

Common sense comes into play, too -- if it seems too good to be true, it probably is. Use your head; you'll probably be right.

=)

In addition to Lance's comments, one other thought about veracity, and reputation of the source.
If the leader of the free world came on TV, and claimed that North Korea was on a massive nuclear weapons delivery program, and was stockpiling chemical and biological weapons for attack against american forces, and was training terrorists with the help of Osama bin Laden for world wide terrorism. Would this statement have credibility? Please, no politics, I offer it as an example...the same thing happened to Henny Penny when the sky was falling.
So, add veracity of the source to Lance's list.