I've posted to YouTube the following video commentary, "Warning to U.S. Troops on Hand-Held Lie Detector":

It should be borne in mind by soldiers in the field who are being asked to rely on the PCASS that those responsible for developing it, including most visibly Don Krapohl, who has been DACA's media front man for it, know that PCASS is highly unreliable and have deliberately overstated its accuracy. (In addition to his appearance in the video segment of the MSNBC report, Krapohl was also interviewed on National Public Radio's Weekend Edition on Saturday, 12 April.)

DACA avoided testing PCASS under anything approaching field conditions. The same methodology that was recently used in a field study that found voice stress analysis technologies to be no better than chance could have been used to test PCASS. Why didn't DACA do so before giving PCASS to our troops?

DACA also avoided testing PCASS in situations with a low base rate for deception (such as in screening for spies, terrorists, and saboteurs), preferring instead to conduct its studies in settings with an unrealistically high base rate of deception of 50%. Krapohl and others at DACA know full well that if a lower and more realistic base rate of deception, say as high as 5% were used, PCASS's evident performance as a screening tool would appear much worse, the high number of false positives making the few true positive results of little practical use. Why didn't DACA test PCASS under realistic base rate conditions before issuing it to our troops?

And DACA avoided testing PCASS's robustness against countermeasures, despite knowing full well that Al-Qaeda and Iraqi insurgents have studied them, and any operatives sent to infiltrate U.S. installations, knowing that they're going to be tested either by polygraph or PCASS, are likely to learn how to fool such tests. Why didn't DACA test PCASS against countermeasures before issuing it to our troops?

As Bill Dedman of MSNBC pointed out in his report, DACA is deliberately overstating PCASS's performance in the unrealistic laboratory tests to which it was subjected by omitting inconclusive results when calculating its accuracy. There is no scientific ground for doing this: it's willful fraud. DACA is lying to the American people, and to our troops. DACA is touting an accuracy rate of 82-90% based on (again, unrealistic) laboratory studies. But the true accuracy rate based on those studies is only 63-79%. Under field conditions, with realistic base rates, and with subjects knowledgeable about countermeasures, much lower accuracy rates than this latter range of 63-79% can be reasonably expected. And DACA knows this.

As a former soldier, interrogator, and linguist, I'm outraged that DACA is foisting this rubbish on our troops. I encourage all to tell your friends, relatives, and acquaintances in the armed forces about the MSNBC report on PCASS and the commentary here.

This is just ridiculous.  Even if you are upset with George for making information about beating the PCASS more widely available than it otherwise would be, thereby compromising the system unacceptably, wouldn't part of the response include, I dunno, not using the PCASS?

"Sir, the enemy has cracked our code--apparently we've been betrayed!"

"Well, keep using it!  Even if they can read all our messages now, that information wasn't supposed to get out.  Besides, I get kickbacks for ever encoded message we send!"

Does that make any sense?  If it has been compromised--however that happened--stop telling people to use it!  Oh, wait, I forgot.  Logic isn't typically used among polygraph proponents.  Sorry, my bad.

It doesn't surprise me that you don't know much about logical fallacies, given your great propensity to use them.  But, for future reference, the correct term is "ad hominem attack", not "ad hominid attack."

And even though you are an AARP member, I still think you would be displeased if your life's work were repudiated.

But, c'mon, it has not been tested in realistic circumstances.  The conditions of the testing were not at all like the conditions under which the device will actually be used.  Also, look at how low you're setting the bar: a 65% success rate.  Also, truth verification in the absence of a polygraph-like device is not necessarily just 50/50.  Or are you admitting that you've never been able to figure out when someone was lying to you without your device?  Maybe that's why you guys don't realize how ridiculous your lies appear: you don't think anyone could possibly detect them without your box.

skip.webb wrote on Apr 21^st, 2008 at 1:18pm:


If you "teach" your students to treat critical thinking with the disdain which you display for it on a daily basis I've no doubt that you'll need to fail many, many students.  No, on second thought, it's the ones who do think critically who fail while those who have unthinking faith in you who'll be passed.  That's the way it works, doesn't it, Skip?

In any event, the "fancy title" that I alluded to in my earlier post was that of American Polygraph Association President, a post which your formerly held.  I'm sorry that senility has set in even before your 60th birthday.  Actually, no I'm not; it couldn't have happened to a nicer guy.  Perhaps cancer is next for you?

Brother Lethe

The troops are going to use something to assist in assessment.  The choice is CVSA,  PCASS, or nothing.   As a nonbeliver you would choose nothing?

pailryder wrote on Apr 22^nd, 2008 at 11:57am:


This really makes no sense.  As long as you believe the troops are going to use something, the accuracy (or lack thereof) of whatever they use is not important?

This isn't far from the often-heard argument in favor of the polygraph that goes something like, "Until something better comes along, we're going to keep using it."  The accuracy of any device that purportedly detects deception is not irrelevant when determining if that device is useful or not.

If the troops are going to use something that doesn't work it is reasonable to warn them of that.  Allowing them to incorrectly believe that their new handheld lie detector can actually detect lies with a high degree of accuracy simply because "they're going to use something" is senseless.

If our nation's airports were going to be supplied with metal detectors that detected metal 50% or 60% of the time, would it be unreasonable to warn people of that fact?  Or would it be better to remain silent because the airports are going to use something, so whatever they use is better than nothing?