Test and Evaluation Report for the Manual Domestic Passive Profiling System (MDPPS) [open pdf - 2MB]
"Increases in threat conditions can result in a requirement for additional security precautions at airports. These precautions are often resource intensive for the airlines. The cost of additional airport security systems, however, could be reduced if the number of passengers needing special security measures was minimized. This report discusses the results of increasing airport security by manually evaluating passenger 'profiles' to identify domestic travelers thought not to represent a threat."
Defense Technical Information Center (DTIC): http://www.dtic.mil/dtic/