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Are You on the No Fly List, Too?

Homeland Security continues to use an algorithm that is approaching 100 years of age to deal with a 2007 problem. It finds about 85% false matches.
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A few years after the Department of Homeland Security developed its No Fly List and No Fly Watch or "Selectee" List, the Washington Post and San Francisco Chronicle reported the screening system was based on an algorithmic software known as Soundex. A crude, antiquated algorithm developed in 1918 to analyze U.S. Census data, Soundex is based on the English language and, as a result, has a few deficiencies when it comes to trying to match Arabic names. Soundex works, generally, by removing vowels from names and then assigning numerical values to the remaining consonants.

This has been the basis for the Computer Assisted Passenger Pre-Screening System (CAPPS) and it is horrendously inadequate and matches far too many names. To see just how poorly Soundex performs, visit and type in your name to assess your chances of being on the No Fly or Watch List. This is the only known publicly available site for checking your name against potential terrorist identities and databases. It was developed by S3 Matching Technologies of Austin, Texas. The company's database technicians merged the best known data on terrorists with the Soundex system to create the site.

S3's system was partly a product of my own curiosity. I have been on the No Fly Watch List for two years and two months, in spite of the fact that I have one of the most mundane names in the English language, have never been arrested, pay my taxes on time, and turn into a whimpering sap at the playing of the National Anthem. Of course, I have also written three books critical of the Bush administration and many people suspect I am on the No Fly Watch List for political reasons. I have my doubts. But the fact that I am on the list is unacceptable whether it is the result of politics or just simple technological incompetence on the part of the federal government.

I do some communications consulting work for S3 and during discussions with the company's executives I was made abundantly aware of the potential shortfalls in Homeland Security's search algorithms for its databases. Soundex only matches names and companies like S3 produce sophisticated software that can match other fields of information like birthdates, addresses, age, and numerous other data points. Of course, this raises the issue of privacy. In our free society Americans are supposed to be able to travel and move about as they wish without surrendering information about themselves. Homeland Security has, nonetheless, pressured the airlines to turn over passenger data and has claimed it is finalizing work on an improved search system known as CAPPS II.

CAPPS II is supposed to add at least two additional data points to the search. The government is expected to ask for your home address and birth date when you check in for a flight. Obviously, this is private information and constitutional challenges are expected to this added requirement. However, database experts like those at S3 indicate personal information is not required to improve the search technology. Matches can be run using already available information like travel patterns, airlines used, types of tickets purchased, and other factors. The invasion of privacy can be avoided and the system can be made better.

In the interim, however, Homeland Security continues to use an algorithm that is approaching 100 years of age to deal with a 2007 problem. It finds about 85% false matches, as you will see when you type your name into By using software from this century, and still matching nothing more than names as data points, the federal government could improve the system by a minimum of 50 percent and remove tens of thousands of innocent travelers from the list. The current system tags so many airline passengers that TSA screeners are too busy dealing with non-terrorists to notice if any of the real bad guys slip past. Obviously, the government has never offered any evidence its present screening technology has ever nabbed a potential terrorist.

In the meantime, Homeland Security has put up a new web site asking you for personal information if you think you are wrongly listed and want to be removed from the data base. The Travelers' Redress Inquiry Program is supposed to facilitate an easy removal of your name from the No Fly lists, if you have been incorrectly tagged by Soundex. I have already proved my citizenship to TSA and Homeland Security dozens of times with similar documents as those required by the TRIP site. But I remain on the list, as do thousands of other innocent Americans. Regardless, I have filled in the TRIP forms and have sent in the requisite copies of documents.

And some day I hope to learn if I am a victim of politics or simple government incompetence.

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