Accuracy questioned in military's hand-held lie detectors

U.S. soldiers in Afghanistan will be issued hand-held lie detectors this month, but Bill Dedman of MSNBC.com uncovered conflicting evidence about their effectiveness. "The Defense Department says the portable device isn't perfect, but is accurate enough to save American lives by screening local police officers, interpreters and allied forces for access to U.S. military bases, and by helping narrow the list of suspects after a roadside bombing." The Pentagon, in a PowerPoint presentation released to msnbc.com through a Freedom of Information Act request, says the PCASS is 82 to 90 percent accurate. But other studies obtained by msnbc.com show that testers discarded inconclusive readings when calculating its accuracy.