If you are a qualified applicant and you keep getting disqualified for nothing more than a "failed" polygraph, just keep trying.

I failed three before passing my fourth and getting my current job in law enforcement.  

Oddly enough, even though I gave the same answers on all four tests (because it is easy to keep telling the truth no matter how many times you are asked) I failed for a different subject on each test.

I would have thought that if I "showed deception" on my drug-related questions on my first test that I would have also shown some deception on drug-related questions on the following three tests.  Nope.  Same answers on test one, two, three, and four, and only on test one did I "indicate deception."

On test two I did fine on the drug questions but "showed deception" with regards to fighting and assaulting people.

On test three I did fine on the drug questions and on the assault questions, but "showed deception" on qeustions about stealing.  Hmmm...  Maybe they think I stole something between test #2 and test #3.  And then I must have returned whatever I stole before test #4, because I didn't show any deception on that one.

It is experiences like this that make me feel qualified to share my opinion regarding the accuracy (or lack thereof) of the polygraph, despite not having been an examiner or conducted a set number of polygraph examinations in the field.