90% false positive screening is too optimistic
Sep 26, 2007, 11:16 am
#1
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90% false positive screening is too optimistic
http://www.usatoday.com/travel/fligh...etection_N.htm
Airport security arsenal adds behavior detection
The man in his 20s looks around the terminal as though he's searching for something. He chews his fingernails and holds his boarding pass against his mouth, seemingly worried.
...The TSA has trained nearly 2,000 employees to use the tactic, which is raising alarms ...
Hawley, who has emerged as the government's leading behavior-detection advocate, says automated detection "is in the far distant future." The TSA's present system, he says, "is phenomenally successful" — even if more than 90% of questionable people turn out innocent.
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This post is not to say behavior recognition is bad. However, 90% innocent is far too optimistic.
If there is a terrorist attack every 3 years conducted by a group of 6 terrorists, then that's 2 terrorist per year. They will not be stopping 20 people per year in the entire country. 18/20 is a 90% innocent rate. Rather, TSA will stop thousands of people and catch 0 to 1 terrorist. People bringing a gun by mistake will act normally because they've forgotten about the gun in the handbag.
I think the program's intent is good. It's just that the innocent rate will be in excess of 99%. Catching terrorists is hard!
Airport security arsenal adds behavior detection
The man in his 20s looks around the terminal as though he's searching for something. He chews his fingernails and holds his boarding pass against his mouth, seemingly worried.
...The TSA has trained nearly 2,000 employees to use the tactic, which is raising alarms ...
Hawley, who has emerged as the government's leading behavior-detection advocate, says automated detection "is in the far distant future." The TSA's present system, he says, "is phenomenally successful" — even if more than 90% of questionable people turn out innocent.
----
This post is not to say behavior recognition is bad. However, 90% innocent is far too optimistic.
If there is a terrorist attack every 3 years conducted by a group of 6 terrorists, then that's 2 terrorist per year. They will not be stopping 20 people per year in the entire country. 18/20 is a 90% innocent rate. Rather, TSA will stop thousands of people and catch 0 to 1 terrorist. People bringing a gun by mistake will act normally because they've forgotten about the gun in the handbag.
I think the program's intent is good. It's just that the innocent rate will be in excess of 99%. Catching terrorists is hard!
Sep 26, 2007, 1:29 pm
#2
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And just what are those 10% of "questionable people" guilty of? They certainly are not terrorists or we'd be hearing about hundreds being arrested every day. If they're no danger to aviation then we shouldn't be detaining them. Airport checkpoints are supposed to make sure that air transportation is safe, not that people have paid their child support, parking tickets, etc.
Sep 26, 2007, 2:38 pm
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Sep 26, 2007, 9:43 pm
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And just what are those 10% of "questionable people" guilty of? They certainly are not terrorists or we'd be hearing about hundreds being arrested every day. If they're no danger to aviation then we shouldn't be detaining them. Airport checkpoints are supposed to make sure that air transportation is safe, not that people have paid their child support, parking tickets, etc.
I've been questioned more than 10 times. Does that mean they think I'm a terrorist sometimes and not other times?
Sep 26, 2007, 10:25 pm
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Speeding, stealing (pencils, pens, etc.). The stuff everyone is guilty of.
If the system catches more than a few dozen people a month, fewer than 1% of the people accused of being threats will actually present a threat. Of course that would mean that most agents doing the assessment flag fewer than one person per month.
In reality fewer than 0.01% of accused parties will present any threat. (The numbers are made up, but probably conservative).
If the system catches more than a few dozen people a month, fewer than 1% of the people accused of being threats will actually present a threat. Of course that would mean that most agents doing the assessment flag fewer than one person per month.
In reality fewer than 0.01% of accused parties will present any threat. (The numbers are made up, but probably conservative).