

TSA to Commission Independent Study of X-Ray Body Scanners - ceejayoz
http://www.propublica.org/article/tsa-to-commission-independent-study-of-xray-body-scanners

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savrajsingh
Assuming it's a real study and they actually gather new data and run some
experiments, what are the possible results?

1) The machines are unsafe and should be removed immediately

2) The machines are unsafe for people that pass through them at some given
frequency (like 5x a year or something)

3) The machines are completely safe

4) ?

Results 1 and 2 would mean that many air travelers would feel entitled to some
sort of compensation.

There's going to be a lot of external pressure to find result #3, so I'm glad
it's an 'independent' study.

~~~
digikata
My issue is with what threshold of safety should be considered. If for
example, the X-ray dose causes one fatal cancer in a million, it would be a
positive risk-benefit for many medical procedures, but for the rate of actual
terrorism attempts vs air travelers getting that dose millions of times over,
the risk benefit seems pretty negative. This is especially true if you're a
frequent air traveller and could be dosed two or more times per trip. That
really means that airport X-ray machines should be held to a much higher
safety standard then medical x-rays.

~~~
pdonis
_My issue is with what threshold of safety should be considered._

That's a good question. The numbers TSA gives, which are quoted in the
article, are that a single exposure to the X-ray scanner gives you the same
radiation dose that you get from two minutes of airline flight. So if we think
the risk of the scanner is unacceptable, we should also consider it
unacceptable for a flight to be lengthened by two minutes. Flight times
routinely vary by more than that due to re-routings for things like weather,
air traffic control, etc.

Nothing is 100% safe. If we are going to try to consider thresholds of safety,
we have to consider _all_ possible risks, not just the ones the media is
currently harping on. What we find when we do that is that we routinely accept
risks far greater than the ones the media is currently harping on. But those
risks don't sell papers or keep people watching.

~~~
digikata
The minutes of flight are there because they're a fundamental part of travel
and are unavoidable if you choose to travel by air. An x-ray machine is there
only for the purpose of additional security. If the risk undergone for the
machine outweighs the security benefit then the machine can and should be
removed. In my mind, there is no equivalence between the unavoidable risk and
the completely avoidable risk.

~~~
krschultz
A lot of flight time is unnecessary. The technology to more efficiently route
airplanes exists, we just have not yet allocated the money to do it. If it
turns out that the X-rays really are no worse than 2 extra minutes of flights,
I'd rather put the money towards improving the air traffic control
infrastructure. Then we save time, reduce radiation exposure, and likely
reduce the risk of an airplane crash. Seems like a better use of money to me.

~~~
digikata
Airlines are already optimizing for flight times - time in the air is fuel
burn which is a major cost input for the business.

If your purpose is to save lives, and have some amount of money you're intent
on spending to do so, there are many better opportunities to get better bang
for your buck than either airport x-ray machines, or shortening flight times.

What really bothers me is that I think that politicians and TSA bureaucrats
have placed an outsized symbolic value on air security via X-ray machine, and
setting in place a policy which causes real harm in sicknesses that are
essentially unlinkable to the machines. Without a detailed and critical look
at the effects, there will be no obvious red flags that people are literally
dying for symbolism.

~~~
pdonis
_Airlines are already optimizing for flight times - time in the air is fuel
burn which is a major cost input for the business._

Airlines certainly try to do this, but they don't control either the weather
or the air traffic control system. That said, I don't disagree that further
optimization for flight times is likely to have a low payoff compared to lots
of other things. My only point is that any flight time optimization that's
worth more than two minutes per flight, on average, must, of necessity, have a
_higher_ payoff than changing the type of scanners at the checkpoint.

 _politicians and TSA bureaucrats have placed an outsized symbolic value on
air security via X-ray machine_

This argument applies to any type of scanner, not just an X-ray one. It
applies equally well to the millimeter wave scanners that the article mentions
as the chief alternative to X-ray scanners. And it in no way affects the point
that the additional risk due to the X-ray scanner, given that you have already
accepted the risk of a flight, is negligible.

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jessaustin
Too bad they won't do a study of how useless the entire TSA is. It wouldn't be
hard: just randomly choose a group of airports that are allowed to go back to
the previous model of private inspectors hired by the airlines. For every year
that goes by with the experimental group of airports having better financial
results, better security, smoother operation, and fewer passenger hardships, a
few more airports will win the lottery and be allowed into the experimental
group. Eventually the TSA will be studied out of existence.

~~~
untog
Well the entire purpose of the TSA is security. And how do you evaluate
security? The number of successful attacks on airports?

Hopefully both the test set and TSA set would have a result of zero. And even
if they didn't, you can't say for sure that it was because of TSA presence. So
the test would be inconclusive, and we'd end up keeping them around "just in
case". After all, we haven't had another attack like September 11th, so the
TSA must be working, right?

~~~
jessaustin
If you define security as "how many commercial airplanes have been flown into
tall buildings", you're probably right. However, I'd also like to include such
measures as "how many items have been stolen by TSA agents from luggage", "how
many times does the TSA violate its stated policies", "how many bins of
'potential explosive materials' are stockpiled at security checkpoints", "how
many times do red-team tests result in missed dangerous items", etc.

Really I think you could use any measure of security, even one picked out by
TSA personnel, and the TSA as currently constituted would do worse than a
private contractor reporting to the airlines. (Even if I'm wrong, wouldn't we
want to know?) The important thing is that security must be balanced against
the other things I mentioned: cost of the security program, indirect costs
borne by airports and airlines, and passenger experience. From a societal
perspective, we also have to weigh the costs associated with encouraging
travelers to drive rather than fly.

~~~
pdonis
_how many items have been stolen by TSA agents from luggage_

As far as I know, the amount of theft due to TSA is negligible; virtually all
of it is due to airline employees.

~~~
jessaustin
I suggest googling for "tsa theft"; if they're firing hundreds of people a
year every year it isn't a negligible problem. But even if more is stolen by
airline employees than by TSA agents, that isn't a defense of the TSA. We
couldn't fly without the airlines; we flew for decades without the TSA.

~~~
pdonis
_if they're firing hundreds of people a year every year it isn't a negligible
problem_

From what I can see from a Google search, "hundreds" is the total number of
TSA people who have ever been fired for theft, not the number per year.

~~~
jlgreco
Given the the low end of "hundreds" and the time the TSA has been in
existence, that is still not negligible.

 _Particularly_ if they suck at catching/firing people as much as they do at
any other sort of screening.

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vaadu
<tinfoil_hat>

The plan is for the scanners to fail the tests

TSA apologizes

Congress indemnifies scanner manufacturers

TSA buys new scanners, which is the overall goal

Scanner manufacturers aka campaign contributors profit

Congressmen get reelected

</tinfoil_hat>

~~~
walru
Pretty much.. You knew there had to be a version 2.0 that we had to buy at
some point.

To be honest, the whole process becomes invalidated when you can now pay via a
program called TSA PreCheck (<http://www.tsa.gov/tsa-pre%E2%9C%93%E2%84%A2>)
to skip the lines entirely.

Theater at its finest.

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w1ntermute
The company that makes these scanners will just take some senators on a few
more all-expenses-paid trips to Hawaii for some "conferences" and things won't
change at all.

~~~
r00fus
Hawaii is too mainstream, more like the Mariana Islands:

[http://www.dailykos.com/story/2007/10/23/401675/-Meet-the-
Ta...](http://www.dailykos.com/story/2007/10/23/401675/-Meet-the-Tan-Family-
corrupt-patrons-of-the-GOP-HRC)

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JagMicker
My biggest concern is regarding the internal software and dosimetry controls.
Could there be a fault condition that would result in unintended levels of
ionizing radiation? It wouldn't be the first such accident..

<http://bjr.birjournals.org/content/78/934/913.full>

[http://www-pub.iaea.org/MTCD/publications/PDF/Pub1207_web.pd...](http://www-
pub.iaea.org/MTCD/publications/PDF/Pub1207_web.pdf)

~~~
Wingman4l7
...And the Therac-25 / airport scanner comparison comes full circle:
<http://news.ycombinator.com/item?id=4919666> =)

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pavel_lishin
> _But it is unclear if the academy will conduct its own tests of the scanners
> or merely review previous studies._

The most important fact that could possibly be presented, and it's not
presented.

Signal to noise ratio is basically nonexistent.

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IanDrake
Sadly, there's only one way to test these machines right. And that's in the
field, as they're being used, without any knowledge that they're being tested.

I'm sure that's not what they're planning to do.

~~~
revelation
If that is the only way, then the conclusion is obvious.

~~~
stcredzero
Can you elaborate?

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mtgx
I don't think I'll trust the results of this. It sounds too much like they
found an "independent" group to study it, and then pressure them into giving
them the results they want.

I would've rather seen an independent group take the initiative themselves and
ask TSA to let them do the testing, at least.

~~~
morpher
The National Acadamy of the Sciences is not just some random "independent"
group. Of course, the article states that it's still unclear as to whether
they will take more data, or simply review existing studies. Likely, they will
do a review first to decide if further study is necessary (e.g., if the
methodology used in prior studies was, in fact, unsound). In any case, having
unaffiliated scientists consider the issue is a step in the right direction.

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DenisM
It's a bit like if I have commissioned a study on whether or not my new
startup is awesome. It could be good if I wanted to find out the truth, but
it's worthless if I am ordering one of those for external consumption. He who
pays the money orders the music.

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geofft
My biggest problem with the scanners is that they are a waste of taxpayer
money, so I'm not particularly thrilled by spending more taxpayer money to
determine exactly how much a waste of taxpayer money they are.

~~~
ghurlman
Sunk costs are just that... sunk. Spending X money now to (hopefully) prevent
spending X + Y money in the future is ideal.

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breakyerself
I doubt the commission will study the 4th amendment constitutionality of the
scanners.

