I'm not sure about the data source, but my query on my situation seems to be accurate (base salary was roughly matching).

As a citizen the salaries are almost double my rate for same position/same company.

Is it a large or small company? How long have you been there? Are you looking only at the base salary part? (e.g. for the reference my total compensation is almost double than my base salary)...

I've decided that due to company policies I shouldn't really say much more.

It is illegal for companies to retaliate for your discussing your salary (though probably not for calling them a "liar"). Look up the National Labor Relations Act.

That being said, you can be fired for things that you're legally allowed to discuss, and then it becomes an issue of whether you're willing to pay lawyer's fees to sue. Which is not usually a great situation to be in.

i don't know but it has matched up with friends' salaries at smaller companies so i trust its data