TSA Adopting Dubious "Chat Downs" While Ignoring Targeted Screening

Aug. 22, 2011 - PRLog -- The TSA has begun [8/15] testing "chat downs" - in addition to pat downs - before mandating the new technique nationwide, even though the process apparently lacks statistical or scientific validity, while ignoring an effective search enhancement technique based upon well-established mathematical principles, says public interest law professor John Banzhaf, who is a constitutional scholar as well as the mathematician-inventor of the "Banzhaf Index."

Chat downs, a form of behavioral profiling in which passengers are required to answer questions from a TSA agent who then instantly scrutinizes the way they respond, are being tested at Boston's Logan Airport before being implemented across the entire U.S., even though the brief [8/15-10/15] test may not produce statistically significant results, at least according to a letter sent to the TSA from the ranking member of the House Homeland Security Committee.

Others also have significant doubts as to whether such techniques can be reliable, given both the huge number of passengers boarding every day, and the problems of training and supervising so many TSA agents even regarding simpler tasks such as spotting weapons concealed in carry-on bags.

"When test after real world test has shown agents unable to even reliably detect weapons on passengers' persons or in their bags, it's hard to believe that these agents can be trained to detect 'micro expressions' which occur in a small fraction of a second, or reliably interpret Adam's apple movement," says Banzhaf.

In sharp contrast, there is a well established mathematics of selecting and testing which is used thousands of times every day to detect everything from rare genetic disorders to manufacturing defects on an assembly line.  Not surprisingly, it is based in large part on concentrating searches where one is most likely to find a problem, rather than ineffectively treating all subjects equally.

Targeted screening is clearly effective, says Banzhaf, noting other areas where it is commonly used.  Screening for Tay-Sacks disease is concentrated on Jews, and for sickle-cell anemia on African Americans.  Screening for breast cancer is concentrated on older women, even though younger women - and even a few men - may have the disease.  Similarly, products with a higher history of defects will be selected more often on the assembly line for examination that those with a lower probability of having faults, says Banzhaf.

Applied to situations like airport screening for terrorists, a very detailed mathematical study shows that treating all passengers equally - and selecting elderly Asian females and toddlers for secondary screening no more frequently than young Muslim males - is illogical as well as very inefficient in stopping terrorist attacks.

Instead, the study shows that certain groups believed to present a substantially higher risk than others should be selected for screening more frequently (but not exclusively) - a frequency determined not by the magnitude of the increased risk they present, but rather by the square root of that increased risk.

As a simple mathematical example, assume that, on the average, only 1 in every 10 passengers can be subjected to a thorough secondary screening.  If young Muslim males are perceived to present a risk which is 9 time higher than the average passenger (even though the overwhelming majority of young Muslim males are not terrorists), at least 3 (the square root of 9) out of every 10 should be selected for secondary screening.  In this way scarce resources are most effectively concentrated where the greatest chance of a problem lies, even though all passengers will still be subject to some chance of being selected for secondary screening.

The TSA seemingly refuses to even consider openly using this logical and established technique - even though it reportedly has used it indirectly and therefore less efficiently - because of wide spread beliefs that it is unconstitutional or unfair to people in higher risk groups, says Prof. Banzhaf, who is also known for applying a similar "square-root" rule to measure voting power under the Electoral College.

But the U.S. Supreme Court has ruled that factors such as race - much less religion, gender and age - can be used in making selections, provided that it serves a compelling governmental interest, and that it is not the only factor used.  That's why state universities may consider race in their admissions process, notes Banzhaf, suggesting that preventing fatal terrorist attacks is an even more compelling governmental interest than increasing racial diversity in classrooms.

Even the Justice Department has proclaimed that, while factors like race cannot ever be used in criminal investigations unless there is a clearly identified suspect of that race, race and similar factors may constitutionally be considered in protecting homeland security and preventing terrorist attacks, even if there is no specific suspect, provided only that it is not the only criteria considered.

In the case of terrorists, Banzhaf suggests, these other criteria might include dress (e.g., wearing bulky or heavy clothing in warm weather), carrying a backpack, behavior (e.g., nervousness or inappropriate sweating, absence of eye contact, pacing, etc.), and age or gender. In short, a young Muslim male who is nervous and also carrying a backpack may constitutionally be given greater scrutiny than an calm elderly Asian female carrying only a small purse.

If members of groups with a higher risk potential were singled out more frequently for secondary screening, everyone would benefit, including members of those very groups. We would be more likely to stop potential terrorists and at a far lower cost, and even innocent young Muslim males would benefit because lines - and the waiting time on them - would be much shorter for everyone (including young Muslim males) because of the decreased inspection time being spent on most low risk passengers.

After all, says Banzhaf, it's the total time spent on undergoing security procedures which is the most important concern for most passengers, and that would be reduced for everyone using a system employing targeted screening based in part on criteria like religion, sex, and age.

Everyone is concerned about not being blown up, and also about not missing their plane because of inspection delays. Concentrating on those most likely to be involved in complex terrorists conspiracies would benefit the great majority of young Muslim males who are law abiding since it would increase their chances of not dying in flight, and also of not missing their flight due to security delays.

"If I could be assured of a substantially greater probability that airline bombers would be detected - and also that waiting time on security inspection lines would be significantly reduced - if only I agreed that people in my category be subject to a longer and more intense search process, I would gladly agree," says Banzhaf.

Banzhaf, who is white, says that he would support such a procedure if credible threats from white separatists to bomb planes were received in South Africa, and  those with a white skin were then singled out for enhanced scrutiny procedures.

JOHN F. BANZHAF III, B.S.E.E., J.D., Sc.D.
Professor of Public Interest Law
George Washington University Law School,
FAMRI Dr. William Cahan Distinguished Professor,
Fellow, World Technology Network,
Founder, Action on Smoking and Health (ASH)
Creator, Banzhaf Index of Voting Power
2000 H Street, NW, Suite S402
Washington, DC 20052, USA
(202) 994-7229 // (703) 527-8418

# # #

John F. Banzhaf III is a Professor of Public Interest Law at George Washington University Law School [http://banzhaf.net/] where he is best known for his work regarding smoking [http://ash.org/], obesity [http://banzhaf.net/obesitylinks.html], etc.