A letter to my congressmen/women

[eve11]

Dear [Senator/congressperson],

I have been following closely the debate over the new airline imaging (AIT) X-ray machines, either the Backscatter machines or the Millimeter Wave machines, and the alternative measures that are being implemented across our nation's airports. I fly three to four times per year, and I am worried about the use of these machines.

I have compiled a list of questions that I would like the TSA to answer, and if you are in the position to ask the higher management, and to publicize the answers, please do.

Questions:

1) What is the procedure for persons traveling alone with babies/small children? My sister has to travel from the west to east coast over the Thanksgiving holiday. She is traveling alone with a seven-month-old child. She has a one-way ticket and is worried she will be singled out for AIT or extra screening because of this. She will refuse to take her baby through the x-ray machine, which I believe is a reasonable decision. But as I understand it, going through the machine requires persons to set their "belongings" aside, possibly even out of view. I also have read accounts that a person cannot undergo an "enhanced pat-down" while holding a child (please see this blog post http://www.ourlittlechatterboxes.com/2010/11/tsa-sexual-assault.html for a clarification). I hope that the TSA has a policy in place for dealing with this situation. As my sister says, 'it only takes a second' for a child out of view to come to harm. I note that people carry babies through the metal detectors all the time with no problems whatsoever.

2) What are the official guidelines for an "enhanced pat-down"? I have heard anecdotal accounts of policies (run hands under waistband, pat inner thighs with palms facing forward until meeting "resistance", open women's labia through their clothes, etc), but nowhere have I seen official guidelines and step-by-step instructions for an enhanced pat-down. I will be opting out, so I want to know what to expect. I want to know the legal and contractual boundaries, enacted and instructed by the officials in the TSA to their trained officers, that constitute allowable action in an enhanced pat-down. I have been unable to find any documentation for this. I think that this should be released to protect the rights and safety not only of passengers, but also of any TSA staff who are unlucky enough to have to perform these pat-downs.

3) How are the enactment and operational procedures of these new security measures going to be monitored? Will we be able to get measurements, conducted from an independent third party observer, for:
1) the number of people who are subject to body scans
2) the number of people who opt out of body scans when chosen
3) the number of people who consent to body scans when chosen
4) the number of people who consent to body scans and afterward are still subject to an enhanced pat-down because of a flagged anomaly on the screen
5) the number of people who file complaints against the TSA
6) the number of people who are dissatisfied but do not take the time to file a complaint
7) the percentage of airports that provide transparent, fully informative measures for the AIT screening procedures, either through signs or verbal communications

I do not believe that any of this information would be sensitive to national security; therefore I think it should be measured, publicized, analyzed and evaluated.

4) Frequency of pat-downs: Mr. Pistole said in the senate briefing on Wednesday November 17th, 2010, that the occurrence of pat-downs would be "rare". However, by the CBS polls it shows that up to 20% of Americans do not agree with these new techniques. This is a measurement of the American public who have phones, not of travelers who are coming into airports. I am curious as to what the survey results would be like for those who travel. Now for example, for random screenings, if one in every five people does not agree with AIT imagers, then it is not unreasonable to think that out of every 5 people singled out to be sent through the imagers,
a) One person will go through the imager under duress and coercion (as opposed to miss their flights, eat the monetary cost, or subject themselves to an invasive and possibly punitive enhanced pat-down).
b) One person will opt out, and subject themselves to an invasive and possibly punitive enhanced pat-down.

This is possibly a twenty percent rate of pat-downs for the AIT machines, not counting those for whom the machine flags an anomaly. I would like to see, or conduct myself, a scientific test of this hypothesis.

5) False positives. I am a statistician who works in network security. Our work is similar in that we monitor millions of "events" per day, looking for those rare occasions where an anomalous reading is also a threat. In this situation, false positives will vastly outnumber true positives, simply because the rate of true positives in the population is so low.

In medical screenings, this is a widely known phenomenon. In statistics, the specificity and sensitivity of the ELISA screening test for HIV is used ubiquitously in introductory courses as an excellent example of Bayes Rule. See for example this homework question:
http://www.brainmass.com/homework-help/statistics/all-topics/354850

**
The ELISA test for AIDS was used in the screening of blood donations in the 1990s. As with most medical diagnostic tests, the ELISA test is not infallible. If a person actually carries the AIDS virus, experts estimate that this test gives a positive result 97.7% of the time. If a person does not carry the AIDS virus, ELISA gives a negative result 92.6% of the time. Experts also estimate that 0.5% of the American public carries the AIDS virus.

Suppose that someone tells you that they have tested positive. Given this information, what is the probability that the person actually carries the AIDS virus?
**

The 0.977 rate is called the "sensitivity", or Pr(detected given disease)
The 0.926 rate is called the "specificity", or Pr(not detected given not disease)
the marginal probability of disease in the population, Pr(disease), is 0.005.

The question is asking the student to discover the probability Pr(disease given detected). This is done using Bayes rule:
Pr(disease given detected) = Pr(diseased AND detected)/Pr(detected)

Using the probabilities that are given, we can write this as:

Pr(detected|disease)*Pr(disease)/[Pr(detected|disease)*Pr(disease) + (1 - Pr(not detected|not disease))*Pr(not disease)]

The answer is startling to some: if a person is tested at random for HIV, then given a positive test, there is only a 6% chance that the person has the disease. That means that 94% of the time, when applied randomly, a positive result is actually a false positive. In the medical community, these kinds of results are why best practices suggest that screening be applied only when there are other risk factors that raise the marginal probability of HIV considerably. In contrast, the TSA has stated explicitly that "Everyone has to be scanned."

I would like to know the specificity and sensitivity of these AIT machines, specifically in their ability to detect terrorist threats to an airplane. If the false positive rate is too high, what measures will be taken so that ordinary citizens are not harassed unnecessarily on their way to board a plane?

6) Radiation exposure. I would like to see a peer-reviewed, public study of the radiation exposure and threat that the machines pose, when they are used as directed for scanning airport passengers. I believe that this requires that an independent third party observe the persons running the machines in practice, and measurements of radiation exposure as such, especially to the eyes and the groin area, which ostensibly is what the operators are supposed to focus on in scanning.

7) I would like to know what the procedures are for staffing the observation rooms. In my line of work, we work in a secure environment in which all cell phones, transmitters, wireless devices, and cameras must be removed and stored before entering the room. The door is locked during times when no-one is present in the area, and only security staff can unlock it. We badge in to the secure area and pass a security desk that is staffed during all hours when the room is open. We must disable microphones and web cameras from laptops before entering. I would ask that the TSA publicize their security requirements for the persons monitoring the AIT scan images. The machines ostensibly cannot transmit or store images as they are configured, but cell phones with cameras certainly can snap a picture of the screen to send to friends.

8) Public information. How will the TSA publicize the procedures and images that are used in AIT screening, to passengers in the security line who may not be informed? Will a brochure be available? Will passengers be able to see examples of the pictures that are rendered from the body scanners? Will passengers be informed explicitly via signs or verbal communications, that the procedure is optional and that they need say "I opt out" to instead be subject to a pat-down? Will they be informed that they have the option to discontinue all screening without punishment and leave the airport?

9) Policies for alerts. What procedures are taken when an alert is flagged? Are the images from the alerted scan stored, printed, or transmitted? Is the person subjected to an enhanced pat-down, luggage search or other measures? Are the procedures different than when a person is flagged by the metal detector? What happens if a person is discovered to have explosives on their body?
--------------

This list of questions is probably too short; I will most likely think of more. Currently, I have decided that I do not wish to subject myself to added levels of radiation, nor to a digital search of my body underneath my clothes, solely because I wish to board an airplane. This means that if I am selected to go through these machines, I will opt out. However, I also believe that I am being presented with a false "choice" in this matter, as I neither want to submit to an enhanced pat-down. I believe that this is an infringement of my fourth amendment right to be free of unreasonable searches. As such, I will be avoiding flying whenever possible, but sometimes it is a necessity for my work.

I am comfortable removing my shoes, throwing away my liquids, emptying my bags of pocketknives and tweezers, sending my belongings through an x-ray machine, and stepping through a metal detector to possibly be wanded afterward. However, I appear to have discovered a personal privacy "line" that the TSA has just crossed with these new imagers and enhanced pat-down techniques. The TSA may say "4 out of 5 agree with our policies", but the checks and balances in place in our government are there specifically to protect citizens' constitutional rights, not the majority opinion.

Sincerely,
[me]



ETA: Another question: What about those who opt FOR the body scanners to avoid being patted down? From what I hear if the machine "Doesn't capture a good image" (whatever the heck that means), then persons are automatically sent over for a pat-down instead. Anecdotally I've heard that this is not necessarily a "rare" event. Can you instead say "No, hold up the line, and take my picture over again until you get a clear image"? If there truly are only these two "choices" in the foreseeable immediate future, I imagine there are plenty of people who would choose not to be touched, for plenty of different reasons.

EATA: Oh, and I've found out that the reason one can't find information about pat-down procedures is because they are considered "SSI"-- Security Screening Information, considered some kind of sensitive information that isn't allowed to be released. So you are being subjected to a procedure for which you have no idea how much contact, or what kind of contact, is allowable. This sounds like lawsuit city to me. (on edit again): Does anyone know if there have been any FOIA filings to obtain pat-down procedures? I suppose it might count as "sensitive information" or as "internal information" but it might be worth presenting an argument; if a citizen who's broken no laws whatsoever is subjected to a pat-down, does the citizen have the right to know what the limits of these pat-downs are? Otherwise how can you make an informed choice? (The answer, from my friend who works at the GAO, is yes, and yes the requests are denied for the reasons I state).

Links:
http://www.dailymail.co.uk/news/article-1331346/Cancer-survivor-forced-prosthetic-breast-TSA-agents-airport-pat-down.html
http://www.lewrockwell.com/rep/airport-body-scanners.html
http://lewrockwell.com/orig3/monahan1.html
http://www.myfoxtampabay.com/dpp/news/national/screaming-toddlers-airport-patdown-111710

Interesting on that last video, they mention that for minors you can ask the ticket agent at the counter when you pick up your ticket if your child has been selected for extra screening, and if they have, you can ask that they be deselected. If only it would work for the rest of us too.

http://www.nytimes.com/2010/11/19/business/19security.html?pagewanted=1&_r=3&hpw

Young boy strip searched by TSA: http://www.youtube.com/watch?v=skkCpnCm7iM

German "fleshmob" strips in protest against body scanners: http://www.youtube.com/watch?v=N6kBn3cnOo8

MSNBC: The TSA has met the enemy, and they are us: http://www.msnbc.msn.com/id/40298973/ns/us_news-airliner_security/

This one pisses me off: Obama stands by controversial air security screening methods http://www.cnn.com/2010/TRAVEL/11/20/obama.tsa/index.html This guy will NEVER have to go through a scanner or a pat-down. Nor his family.

TSA pat-down leaves traveler covered in urine: http://www.msnbc.msn.com/id/40291856/ns/travel-news/

Israel is the answer? I have had doubts about this; there are people parroting Bruce Schnier and that Israeli security expert all over the net without really knowing all that happens in Israel's layered security model either. http://ifamericansknew.org/about_us/etyt10.html If you visit Palestinians and non-violently protest, you will be detained, strip-searched and cavity searched. If you are of Palestinian descent, you run the risk of being detained and strip-searched.

More TSA horror stories: http://healthznews.com/tsa-pulls-pants-off-71-yo-man-with-knee-implant.html
http://pncminnesota.wordpress.com/2010/11/08/rape-survivor-devasted-by-tsa-enhanced-pat-down/

Letter of response to health concerns from people who actually sound like they know what they are talking about:
http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/SecuritySystems/ucm231857.htm
I am curious what the parameters were so as to ignore population effects. were the recommendations written with as widespread deployment as will likely be ramping up in the next few years?

Comments

[arthurfrdent.livejournal.com]

toots, this is brilliant. you should send copies to your local blogs and news outlets too, just to spread this kind of word around.

The end thing with 4 of 5 agreeing with policies... is an interesting spin. I believe that if you polled the flying public the numbers would be quite different. Many people do not fly very often, or go for years without it. The truth of what this all means doesn't crystalize to them until a surly TSA agent is copping a feel.

[eve11]

I forgot question 9, but I don't want it to be so long that nobody will read it:


9) Policies for alerts. What procedures are taken when an alert is flagged? Are the images from the alerted scan stored, printed, or transmitted? Is the person subjected to an enhanced pat-down, luggage search or other measures? Are the procedures different than when a person is flagged by the metal detector? What happens if a person is discovered to have explosives on their body?

[kalypso-01.livejournal.com]

I agree - i think you should contact as many bloggers/news outlets as you can with this letter.

[astrogirl2.livejournal.com]

*applause*

[livii.livejournal.com]

This is really good, even if the stats make my head spin, haha. I'm so useless at it, but your conclusions were clear!

I really liked this bit: but also of any TSA staff who are unlucky enough to have to perform these pat-downs - yes, they are not even covering their own behinds! I imagine some TSA agents out there are extremely uncomfortable with this as well.

We have to fly at Christmas - well, if we want to see our families - and I'm worried about which to choose, if needed. Oh, and excellent point on babies, I was wondering about that! And at least that mom in the linked blog post had a stroller - I know lots of moms who travel only with a baby carrier. If I was flying alone, I probably would too, but since I have my husband with me, we do use a stroller.

[eve11]

I would hope that they would just let you go through the metal detector if you are traveling alone with a child, but who knows? And oh, another question, are all pat-downs now "enhanced"? or is it just the ones that get flagged from the AIT machines? Because I'll tell you what, every single time I go through the airport I see *someone* standing with their feet on the yellow circles getting wanded or whatever.

Ugh.

[boofadil.livejournal.com]

I love people with smart brains!

[skurtchasor.livejournal.com]

You're assuming that the average politician is going to understand (or even bother to care about) conditional probability? Har, that's a funny one.

[eve11]

well it is a stats 101 question.

Actually, I suppose that empirically one could measure the false positive rate directly in this case. Of course, I suppose they can always start upping the ante for what counts as a true positive. Seriously, is a baggie of drugs a terrorist threat to the plane? I'd think a drug mule would be doing all they possibly could to get to their destination WITHOUT hassle.

[skurtchasor.livejournal.com]

Have you taught Stats 101?

[eve11]

Yeah, twice. To humanities majors. Well, maybe it was stats 102. I also was a teaching and lab assistant multiple times. This is the standard Bayes Rule lab question.

[skurtchasor.livejournal.com]

Did they remember Bayes' (Baye's?) formula for more than ten seconds after the final was over? If so, our experiences vastly differ.

[eve11]

Bayes', and some of them did, I think. possibly for up to a week. ;) I bet a bunch of them remembered the story above, if not the particulars of the math.

[kalypso-01.livejournal.com]

I remember nothing about my stats 100 class, except that I'm pretty sure that we didn't cover this.

[eve11]

It might possibly be second semester introductory, not first semester. But it is introductory.

Also it's quite possible that you were taking stats in about 1996, so it may have taken a bit for it to catch on as a standard stats question.

[skurtchasor.livejournal.com]

It's not technically part of the first semester here, but there is an exercise in our textbook (specifically about the ELISA test) that walks you through the computations without stating the general Bayes' Formula. I assume it would be covered in the next course.

[rabswom.livejournal.com]

I linked to this on FB. It's really smart and those are really reasonable questions.

[eve11]

thanks. feel free to circulate it around.

[snonsumr.livejournal.com]

also posted to fb and gathered several likes on it. :-)

[lem0nb0mbs.livejournal.com]

You win the universe for forever.

[lostrack621.livejournal.com]

amazing and well thought-out arguments. brava!

FYI: Bodyscan information derived from a study by an ASU professor (rec'd by one of my colleagues here at ASU)...

doesn't answer all of your scientific questions, but it's a good starting point IMO.

[spiralsheep.livejournal.com]

I dunno if you've seen this:

http://news.yahoo.com/s/ap/20101118/ap_on_re_us/us_airport_security_private_screeners

[eve11]

It's a good start, but technically, they can op out of the TSA performing the security checks, but as clarified on the TSA blog: "All commercial airports are regulated by TSA whether the actual screening is performed by TSA or private companies. So TSA’s policies – including advanced imaging technology and pat downs – are in place at all domestic airports. "

[pwinkler.livejournal.com]

I'd like to see statistics around the effect the new procedures actually have in achieving their goals (and know exactly what their goals are, really). It's hard to believe we spend millions on this stuff to prevent marginal problems when there are many more likely/common causes of death.

As I understand it, you can't refuse both scan and pat down without penalty. Once you're at that point, you are required to continue with one.

I find it hard to believe that 4 out of 5 people are actually OK with it. I'd like to find out how that survey was run and what questions were asked. Who gets asked "strangers are going to feel around your sensitive bits and/or irradiate you" and says they think it's a good idea?

[eve11]

All valid points. The whole civil fine thing is a joke. I would love to calculate the statistical probabilities of a person going through airport security actually being intent on harming people on the plane. It's just ridiculous all around. I'm done; I'll write the airlines and tell them as much.

[wolfy-writing.livejournal.com]

I'm glad you're asking this. For my job, I have to fly a lot (seriously, the options are "Take lots of plane flights" or "Quit my job"), so this is a scary prospect. Since it's been implemented, I've been overseas (where they don't do anything like this - even in strict countries, there's no "We will routinely feel you up or take naked pictures of you") but I'll be visiting the US next month, and I'm nervous about what this will do.

[eve11]

I think a lot of people are nervous :( The more I read about it the more scared I get. Forget terrorists, I have no idea how I'm even going to handle getting through the airport to my plane because of the TSA.

On the other hand, I'm half tempted to go to the airport in a bikini and trench coat next time I fly.

[wolfy-writing.livejournal.com]

I can't believe this is all over the stupid underpants bomber. Letting some incompetent idiot dictate national policy is a terrible idea.

[eve11]

Not to mention, the underpants bomber completely bypassed security through a simple social engineering trick. He had an upscale 'handler' and a sob story about being a Sudanese refugee. Such BS. That should have been what roused people's suspicions. No, instead the government now says "We need to see under your clothes."

I tell you what, we need someone to take the jerks to court and ask the same question that got McCarthy's pyramid crumbling all around him: "Have you no decency sir, at long last?"

[wolfy-writing.livejournal.com]

Yeah, doing the basics well works better. But security theater is better PR, because a lot of people believe that if it's making you miserable, it must be really effective.

[eve11]

It's ridiculous. I'm curious, would you be able to go through a body scanner if you had to set your crutches aside, put your hands over your head and stand still for 10-15 seconds? Because if not you might not be able to avoid the pat-down if you are selected.

[wolfy-writing.livejournal.com]

That could be tricky, depending on how still they wanted. I can walk through metal detectors no problems, but standing really still is tricky for me.

[eve11]

On their website they only say "for a few seconds", so I don't know exactly what that translates to. There is a propaganda video on their website here that shows examples of people going through the machines, but it doesn't actually show anyone from start to finish (annoying), nor does it say whether or not the persons screened in the video were required to go through additional screening.

[wolfy-writing.livejournal.com]

Hmm. Some people have reported being sent through the backscatter machine and then getting a pat-down afterward because there was a problem with the results.