German Police Admit That Full Body Naked Airport Scanners Suck; 35% False Alarm Rate

from the that's-worse-than-useless dept

We've noted all sorts of privacy and health problems related to full body "naked" scanners -- but there's a separate but important question: do they actually work? There's been some evidence presented that they wouldn't have spotted a variety of recent terrorism attempts, but now German police have noted that the machines also have a ridiculously high false alarm rate:
The weekly, Welt am Sonntag, quoting a police report, said 35 percent of the 730,000 passengers checked by the scanners set off the alarm more than once despite being innocent.

The report said the machines were confused by several layers of clothing, boots, zip fasteners and even pleats, while in 10 percent of cases the passenger's posture set them off.

[....]

In the wake of the 10-month trial which began on September 27 last year, German federal police see no interest in carrying out any more tests with the scanners until new more effective models become available, Welt am Sonntag said.
I would argue that this is actually worse than useless, in that providing a significant number of false positives makes it much, much harder to spot the actual positives. It desensitizes agents to assume that any alarm is a false alarm.
Hide this

Thank you for reading this Techdirt post. With so many things competing for everyone’s attention these days, we really appreciate you giving us your time. We work hard every day to put quality content out there for our community.

Techdirt is one of the few remaining truly independent media outlets. We do not have a giant corporation behind us, and we rely heavily on our community to support us, in an age when advertisers are increasingly uninterested in sponsoring small, independent sites — especially a site like ours that is unwilling to pull punches in its reporting and analysis.

While other websites have resorted to paywalls, registration requirements, and increasingly annoying/intrusive advertising, we have always kept Techdirt open and available to anyone. But in order to continue doing so, we need your support. We offer a variety of ways for our readers to support us, from direct donations to special subscriptions and cool merchandise — and every little bit helps. Thank you.

–The Techdirt Team

Filed Under: airports, germany, scanners


Reader Comments

Subscribe: RSS

View by: Time | Thread


  • icon
    ahow628 (profile), 9 Aug 2011 @ 7:32am

    What do you want to bet?

    I bet none of the body scanning makers are major contributors to German re-election campaigns.

    On the other hand, you know there was major lack of due diligence from the US government because of some lucrative government contract farmed out to a major campaign supporter.

    link to this | view in chronology ]

    • identicon
      Theoden, 9 Aug 2011 @ 8:45am

      Re: What do you want to bet?

      Reminds me of the way the Electronic Voting machines were pushed out to the polls with no way to verify anything that they did.

      Receipt? We don't give no steenkin' receipts!

      link to this | view in chronology ]

  • identicon
    Donnicton, 9 Aug 2011 @ 7:41am

    while in 10 percent of cases the passenger's posture set them off.

    That's just because there haven't been any courses that teach children proper posture anymore.

    I'm sure if we mandated a "government approved posture program", we will see a sharp drop off in false positives due to posture.

    link to this | view in chronology ]

    • icon
      Ninja (profile), 9 Aug 2011 @ 7:57am

      Re:

      That's a public health issue. We should get more money from the Health Ministry so we can make scanners that will ignore the bad posture numbers and thus cover the terrible German health service. Oh.. We were talking about security?

      link to this | view in chronology ]

    • identicon
      Clay, 9 Aug 2011 @ 8:42am

      Re:

      I'm sure if we mandated a "government approved posture program", we will see a sharp drop off in false positives due to posture.

      Well said comrade.

      link to this | view in chronology ]

  • icon
    specialized (profile), 9 Aug 2011 @ 8:00am

    I can picture it now, a 21st century re-boot on everybody's favorite fable, "The Boy Who Cried Wolf."

    The Full Body Naked Scanner that Cried Terrorist.

    link to this | view in chronology ]

  • icon
    FormerAC (profile), 9 Aug 2011 @ 8:01am

    more than once?

    "The weekly Welt am Sonntag, quoting a police report, said 35 percent of the 730,000 passengers checked by the scanners set off the alarm more than once despite being innocent"

    How many set it off only once, despite being innocent?


    "they trigger an alarm unnecessarily in seven out of 10 cases"

    Is that seven out of ten passengers screened set off an alarm unnecessarily? Or only that 70% of the alarms are false alarms?

    link to this | view in chronology ]

  • icon
    Beta (profile), 9 Aug 2011 @ 8:04am

    dream job

    I would love to be the official in charge of investigating how these machines were bought, installed and put into operation before these tests were carried out, and whose signature was at the bottom of all the documents.

    link to this | view in chronology ]

  • identicon
    John Doe, 9 Aug 2011 @ 8:09am

    Just like the alarms at the exit doors of Wal-Mart

    The exit doors at Wal-Mart have a scanner that rarely goes off, but when it does, the employees often times just go over and reset the alarm without checking the person who set it off. Seems there are enough false alarms they consider every alarm a false one.

    link to this | view in chronology ]

    • icon
      freak (profile), 9 Aug 2011 @ 8:17am

      Re: Just like the alarms at the exit doors of Wal-Mart

      With the wal-mart here, it's because the employees are not allowed to accuse the person of stealing, indicate they might be stealing, or even confront someone they think might have set the alarm off by saying: "I think you might have set the alarm off".

      I have no idea why they even have an alarm if they're not allowed to do anything about it ...

      link to this | view in chronology ]

      • icon
        Joe Publius (profile), 9 Aug 2011 @ 8:27am

        Re: Re: Just like the alarms at the exit doors of Wal-Mart

        As a former retail drone, I get the impression that all of the precautions taken against shoplifing are essentially security theater.

        You really can't accuse someone of stealing, but the alarms, the aisle walks, etc exist to give lifters the impression that they are being watched.

        link to this | view in chronology ]

        • icon
          freak (profile), 9 Aug 2011 @ 8:32am

          Re: Re: Re: Just like the alarms at the exit doors of Wal-Mart

          With any other store I've been to, they actually do use those features to catch AND charge people.
          Strangely enough, it doesn't hurt business to kick out those folks who were costing you money every visit. Who knew?

          It doesn't surprise me that wal-mart has such a high shoplifting rate . . .

          link to this | view in chronology ]

      • icon
        Pitabred (profile), 9 Aug 2011 @ 8:34am

        Re: Re: Just like the alarms at the exit doors of Wal-Mart

        Only their "loss prevention" team is allowed to do that. The general employee just needs to ignore it.

        link to this | view in chronology ]

      • identicon
        Nicedoggy, 9 Aug 2011 @ 8:43am

        Re: Re: Just like the alarms at the exit doors of Wal-Mart

        The testing phase perhaps?

        link to this | view in chronology ]

    • icon
      Richard (profile), 9 Aug 2011 @ 9:06am

      Re: Just like the alarms at the exit doors of Wal-Mart

      The exit doors at Wal-Mart have a scanner that rarely goes off, but when it does, the employees often times just go over and reset the alarm without checking the person who set it off. Seems there are enough false alarms they consider every alarm a false one.

      This is also what happened at Chernobyl.

      link to this | view in chronology ]

  • identicon
    Anonymous Coward, 9 Aug 2011 @ 8:15am

    Well, now, let's see. 35%? I would have to imagine that the machines have some parameters for tuning, and perhaps the German units are set to be very sensitive. Are you sure the US units are used the same way?

    What are the standards for a false alarm? The unit blocking an area for further checking? Hmmm, that sounds more like "areas that the machine can't accurately check that require manual inspection" rather than a false alarm.

    Is there like lights and a siren and stuff, or just an operator going "check this person some more"?

    Mike, I know you want these machines to go away, but can you please at least try to not over-hype everything negative you read about them?

    link to this | view in chronology ]

    • icon
      AdamBv1 (profile), 9 Aug 2011 @ 8:32am

      Re:

      It basically means that 70% of the people who pass through these scanners get a false positive and since they say that 35% of the people passing through these scanners set off multiple false positives it seems the immediate recourse to a positive scan is another dose of rads. Once you get that second false positive it would seem you get a manual pat down.

      link to this | view in chronology ]

    • identicon
      Anonymous Coward, 9 Aug 2011 @ 8:55am

      Re:

      What are the standards for a false alarm? The unit blocking an area for further checking? Hmmm, that sounds more like "areas that the machine can't accurately check that require manual inspection" rather than a false alarm.


      That's the same thing as a false alarm as the machine identifies suspicious items or areas. It's not a "bomb" or "gun" detector, it's a detector of odd stuff.

      Regardless, the machine is looking for something that is present on a very small fraction of the people checked. If it identifies 1:3 as being possible violators, it is useless. False alarm rate is very important for sensors/detectors, especially those looking for rare things. Almost every single person who sets the machine off is innocent, so the alarm means nothing.

      link to this | view in chronology ]

  • icon
    Vincent Clement (profile), 9 Aug 2011 @ 8:20am

    The fact that the Israeli Airport Authority does not use body scanners is the best indicator of their value.

    link to this | view in chronology ]

    • identicon
      Anonymous Coward, 9 Aug 2011 @ 8:41am

      Re:

      Yup, they just use techniques that would violate pretty much all of the US constitution, plus large guns on board most of their flagship airlines flights.

      Yeah, somehow I think a pat down is better than giving up all my rights.

      link to this | view in chronology ]

      • identicon
        Urza9814, 9 Aug 2011 @ 10:47am

        Re: Re:

        The government has already stated that your constitutional rights do not apply at airports. That's how they can get away with the pat-downs and such...

        link to this | view in chronology ]

      • icon
        BeeAitch (profile), 9 Aug 2011 @ 3:48pm

        Re: Re:

        So, you'll happily give up some of your rights as long as you're not asked to give up all of them.

        Then, by your argument, your rights can be stripped until you only have one right left.

        The million-dollar question: Which right do you choose to keep? (And do you really believe that you'd be allowed to choose?)

        I don't like you world...

        link to this | view in chronology ]

      • identicon
        Hans, 10 Aug 2011 @ 9:22pm

        Re: Re:

        "Yup, they just use techniques that would violate pretty much all of the US constitution,..."

        Citation please.

        "... plus large guns on board most of their flagship airlines flights."

        Sounds like an excellent deterrent.

        "Yeah, somehow I think a pat down is better than giving up all my rights."

        Yeah, somehow I think that there's no reason for me to lose my rights in order for you to have the illusion of security. If you're worried about flying, then don't fly. But don't expect all the rest of us to get scanned or groped so you can feel better.

        link to this | view in chronology ]

  • identicon
    Anonymous Coward, 9 Aug 2011 @ 9:04am

    The germans don't know how to use the machines properly like the americans do.

    You are supposed to strip down to almost naked BEFORE going into the naked body scanners.

    link to this | view in chronology ]

    • identicon
      Prisoner 201, 9 Aug 2011 @ 1:10pm

      Re:

      Almost?

      Clearly you did not get the latest memo on "standard procedures".

      link to this | view in chronology ]

  • icon
    Casey Mahoney (profile), 9 Aug 2011 @ 9:39am

    Why

    Why things are not tested out before hand.I would hate to be a TSA person these days.You might get hit or punched.

    Thanks Casey Mahoney

    link to this | view in chronology ]

  • icon
    geekwithsoul (profile), 9 Aug 2011 @ 10:28am

    So if there are false positives . . .

    does anyone know the rate for false negatives? If that's higher than a few percent, you kind of have to wonder what the whole purpose of this approach is.

    link to this | view in chronology ]

    • identicon
      Leo, 9 Aug 2011 @ 11:15am

      Re: So if there are false positives . . .

      Well...
      If I remember correctly, only one terrorist attempt has been made in a plane since the porn-scanners are in use. This terrorist was captured on the plane, not by the scanner.

      Terrorists might have been captured by the scanners before boarding the plane. But I never heard about this. And whatever the number, it is vanishingly small compared to the number of normal passengers just flying from A to B.

      The number you are looking for is either 100% or incomputable.

      link to this | view in chronology ]

    • icon
      aldestrawk (profile), 9 Aug 2011 @ 11:32pm

      Re: So if there are false positives . . .

      That rate is probably considered SSI, if not classified. A general target range for both FAR and FRR in security detection scanners is given as 1%-5%
      http://onlinepubs.trb.org/onlinepubs/tcrp/tcrp_rpt_86v13.pdf

      link to this | view in chronology ]

  • icon
    Jeffrey Nonken (profile), 9 Aug 2011 @ 11:01am

    Makes me think of store security scanners...

    You know, those silly things they put on either side of the door that beeps when it sees a security strip that hasn't been zapped? It's funny to watch the clerks in a store when the alarm goes off -- they don't even look up. Somebody could be taking the entire liquor aisle and they wouldn't notice.

    "The Boy who Cried Wolf" is more than 2500 years old and is embedded in our culture, even to having its own idiom, and we haven't figured it out yet. Well, it looks like the Germans have. I guess we're not as smart as they are.

    link to this | view in chronology ]

  • identicon
    steve2, 5 Nov 2011 @ 11:04am

    The scanners give off radiation which makes them a health risk. We aren't being kept safe if we're being hit with radiation. There's already a million sources of radiation in society. Cell phones, laptops, and flatscreens are a few sources. There's many others. We don't need these scanners that aren't even reliable to damage us with more radiation.

    link to this | view in chronology ]


Follow Techdirt
Essential Reading
Techdirt Deals
Report this ad  |  Hide Techdirt ads
Techdirt Insider Discord

The latest chatter on the Techdirt Insider Discord channel...

Loading...
Recent Stories

This site, like most other sites on the web, uses cookies. For more information, see our privacy policy. Got it
Close

Email This

This feature is only available to registered users. Register or sign in to use it.