pandasn wrote on Feb 28^th, 2014 at 2:53pm:

Twice. I failed it twice. The band that went around my middle was too tight the first time, which prompted me to take really huge breaths. The polygrapher yelled at me. So I started to really try not to take those big breaths, and he yelled at me for using countermeasures. Then I was so flustered from his telling me that I was lying that I started twitching in the chair which apparently looked like MORE countermeasures. Needless to say, I failed that one. He said I was unresolved on everything. They gave me another chance - and I also screwed that one up because I was dreading it so much and of course the band is still too tight. He loosened it once but that did not really help. Then they each grilled me for about two hours about what I was hiding. FYI: I have done NOTHING wrong. I am a really good kid. I declared minor (5 times) marijuana usage and minor instances of illegal downloading on my form. Everything I reported is true (and I omitted nothing). For what it is worth, the polygraphers seemed to believe me that I wasn't doing it on purpose and that I was telling the truth when I said that I was hiding nothing - but they were still awful to me. I cried a lot in the first one and a little bit in the second one. I just want to ask everyone - what are my chances that they will still grant my clearance? The rest of my processing has been stellar (to the best of my knowledge). Also, this is for a job with an intelligence agency. I will be so miserable if I don't get it. I'm extremely qualified and I just feel so cheated that the polygraph is doing me in when it's apparently pseudoscience.

The real determining factor will be how much dirt the investigators will be able to "develop" on you during the BI.