Preliminary Credibility Assessment Screening System: U.S. Deploys Hand-Held Lie Detector

[Lethe]

YES!

When the troops use this device and it shows the detainee is being truthful, that means that the detainee is being truthful, that the machine's error rate of 10-50% (whatever you believe it to be) is causing an inaccurate reading, or that the detainee knows how to beat the port-a-poly.

If the device indicates that the detainee is being deceptive, that means the detainee is being deceptive, or they are being truthful but the device's 10-50% (whatever you believe it to be) error rate is causing an inaccurate reading, or that the detainee was trying to employ countermeasures and did such a poor job that it resulted in a "DI" score.

I don't see how that can possibly be an asset to the troops.  They don't know anything more after using the PCASS than they did before using it.  After using the PCASS they'll be taking a guess and putting their lives on the accuracy of that guess.

They could also be issued a silver dollar and flip it each time they question a suspected terrorist.  Sometimes the coin would be right, but would that make it better than nothing?  According to your stated logic, it would.  I disagree.

The Department of the Treasury would be upset with the Department of Defense if they follow your recommendation, Sergeant.  They're trying to promote those new gold dollar coins now, the ones with the presidents on them.  

In more seriousness, it would be very, very difficult, I think, for a soldier to go against the port-a-poly (a clever name that I'll try not to overuse).  If the PCASS indicates deception, but you follow the other information that you have and decide to place some measure of trust in the person, and then anything bad happens, it's likely that your credibility before your men is going to be pretty much shot (but thank God if that's all that gets shot).  

I think polygraphers underestimate the enourmous amount of pressure that will be on soldiers who want to go against the recommendation of the PCASS.  I don't think very many will.  I think it's likely that far too much reliance will be placed on the device.  Thus the need for reliable experimental data produced in tests that more accurately reflect war zone conditions.  Regardless of what data those tests produce, if the PCASS is deployed the troops must know how accurate it is.  

And I really do hope they have the chance to play around with the device and try to beat it.  Whether they can or can't, it'll be a very illuminating exercise.

[George W. Maschke]

Close to the time that Bill Dedman's excellent investigative report appeared on MSNBC, Fox News interviewed Professor Stephen Fienberg, who chaired the National Academy of Sciences/National Research Council Committee to Review the Scientific Evidence on the Polygraph:

http://www.youtube.com/watch?v=JPAbVIEFGB8

[George W. Maschke]

On Friday, 13 June 2008, the Armed Forces Network, Afghanistan, aired a report on the use of PCASS in Afghanistan. Not surprisingly, AFN's reporting on PCASS is completely uncritical, and the segment is more a public relations release for PCASS than television journalism. I've posted the story, along with commentary on YouTube:

http://www.youtube.com/watch?v=uiP5wlYzij0

The video can also be viewed directly on YouTube here:

http://www.youtube.com/watch?v=uiP5wlYzij0