by checking how transparent the source's author is

Yes.

"Credibility" is the state of being believable. An authority or statement a person is likely to believe has a lot of credibility. Sometimes other factors make such a source even more believable; in that case the other factors are said to "lend credibility" to the original statement or source. This means the same as to "add credibility".

E.g. "I generally believe what Mr. X says about unemployment, and this recent report lends credibility to his statements."

1. What are three factors that could contribute to the credibility of a source?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

2.

being about to trust and rely on the message that was given