It is misleading to state that polygraph examiners are skilled at detecting countermeasures when the only proof is that some of the examinees accused of employing countermeasures later admit to doing so.  The clear problem is a lack of scientific control on the method of verification.  A polygraph examiner faces no negative repercussions should he or she wrongfully accuse someone of using countermeasures.  Therefore, there is no incentive for them to withhold their accusations from anyone who arouses even the faintest suspicions that they may be employing countermeasures.

Ironically, the reasoning behind the countermeasure detection issue is remarkably similar to the reasoning behind the use of the polygraph itself:

Countermeasure Detection – Examiners are free to accuse anyone of countermeasure use.  Anyone who is accused and later admits that they were using countermeasures is held up as living proof that countermeasures can be detected.  The unproven accusations are forgotten.

Polygraph Accuracy – Examiners are free to accuse anyone of deception during the “test.”  Anyone accused of deception who later makes a damaging admission or is convicted in court is then held up as a shining example that polygraphs are accurate.  The unproven accusations are forgotten.

Regardless of the specific issue, the methodology is completely illogical and inaccurate.  If one hundred people are polygraphed, fifty of them are accused of countermeasure use, and five of them admit to it, pointing to those five as proof that countermeasures are detectable is laughable.  Likewise, if one hundred people are polygraphed, fifty of them are accused of deception, and five of them later admit to being deceptive, it is ridiculous to point to those five cases as proof that the polygraph can be used to detect deception.