Based solely on distortions made by examiners during  my polygraph at the NSA in March of 2000, the FBI had initiated an investigation of me for possible espionage with Taiwan.  The investigation took close to a year, and cost quite a bit of money and valuable time and agent resources.  The case was found to be baseless, and was finally closed with a phonecon between myself with the FBI's Honolulu office nearly a year after the investigation had started!  If only they had called me earlier, I could have cleared up the matter with them, and saved the taxpayers $$!

As for the "distortions".  I served 20 years as a military linguist (Mandarin Chinese).  Two years before retiring (still on active duty) I attended a seminar in Taiwan.  My command knew all about it (they even wanted to pay for it due to the language training value).  Anyway, I had to go to the Taiwan Coordination Counsel in Honolulu to apply to attend the seminar, get a visa..etc.  During one of the trips  I got to chatting with the Officer-in-Charge.  It's not often I got to practice my chinese with a native speaker.  Anyway, he ended up suckering me into translating for free (Chinese to English) a 20 page directive just faxed in from Taipei which set forth new rules for americans wanting to work in Taiwan.  I guess he was too cheap to pay a actual translation service!

He asked me if I would be interested in working for them part time.  Since I was still on active duty, I had to decline.  The job would have entailed acting as a liaison between the local community and the Taiwan office.  Pretty innocuous, and a valid need on their part.  They can easily communicate with me since I am bilingual, and of course, being an american, I can communicate better with locals coming into their office.  But not so innocent according to the ever vigilant dickhead polygraphers at the NSA who see a spy behind every bush...

During my polygraph, the examiner claimed I was being "deceptive" on the "foreign contacts" question.  I told them all about the above contact with Taiwan.  They evidently didn't buy  it, convinced their polygraphic contraption was indicating I was spying for taiwan.  I failed the test, and an FBI investigation was initiated!

I post this as an example of how information volunteeered during a polygraph can be distorted.  It is amazing,  and a bit funny, that they would waste the FBI's resources and time on such nonesense!  

TC

It took around a year.  Still waiting on the FOIA stuff from NSA.

Note, the FOIA package from FBI was mostly blacked out.  Still, I got proof they had conducted an ESP (espionage) investigation on me based soley on the mental machinations of NSA polygeeks.  IOW, it was based on nothing, and they found NOTHING!  I told the FBI SA exactly what I told NSA polygraphers, and they dropped it imediately.

It doesn't pay to be "talkative" during the test in an effort to "bend over backwards to cooperate".  This is what honest people do who have nothing to fear.  Look where it got me!  OTOH, you don't want to "clam up" either.  If you are asked open ended questions, make them elaborate on what they are asking.  Don't get led.  For example, if they say: "Tell me about your trip to Mexico.", your reply should be:  "What would you like to know.", or "Could you be a little more specific please?" 

For example, during the post test interrogation "show", the polygrapher yells:  "OH YEAH!  You walk into the Taiwan embassy and the Officer-in-charge just walks up to you and asks you to translate something....".  I should have just calmly asked:  "When did I say that Ms. polygrapher?"  Answer questions with questions if the question is a distortion.  I'm not saying turn it into a Charles Manson interview.  Just be calm and factual.  If you've ALREADY answered a question.  Respectfully remind them of that, and ask they what EXACTLY they didn't understand about your answer.

Bottom line, if you are showing "reactions", they ASSume you are lying.  Their goal is then to get any juicey little tidbit they can distort to justify their false premise that "reaction" = "deception". 

Sorry for the long winded reply.