[Infowarrior] - The Politics of Paranoia and Intimidation

[Richard Forno]

(c/o BruceS) 

The Politics of Paranoia and Intimidation

by Floyd Rudmin
http://www.lewrockwell.com/orig7/rudmin1.html

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The Bush administration and the National Security Agency (NSA) have been
secretly monitoring the email messages and phone calls of all Americans.
They are doing this, they say, for our own good. To find terrorists. Many
people have criticized NSA's domestic spying as unlawful invasion of
privacy, as search without search warrant, as abuse of power, as misuse of
the NSA's resources, as unConstitutional, as something the communists would
do, something very unAmerican.

In addition, however, mass surveillance of an entire population cannot find
terrorists. It is a probabilistic impossibility. It cannot work.

What is the probability that people are terrorists given that NSA's mass
surveillance identifies them as terrorists? If the probability is zero
(p=0.00), then they certainly are not terrorists, and NSA was wasting
resources and damaging the lives of innocent citizens. If the probability is
one (p=1.00), then they definitely are terrorists, and NSA has saved the
day. If the probability is fifty-fifty (p=0.50), that is the same as
guessing the flip of a coin. The conditional probability that people are
terrorists given that the NSA surveillance system says they are, that had
better be very near to one (p=1.00) and very far from zero (p=0.00).

The mathematics of conditional probability were figured out by the Scottish
logician Thomas Bayes. If you Google "Bayes' Theorem", you will get more
than a million hits. Bayes' Theorem is taught in all elementary statistics
classes. Everyone at NSA certainly knows Bayes' Theorem.

To know if mass surveillance will work, Bayes' theorem requires three
estimations:

   1. The base-rate for terrorists, i.e. what proportion of the population
are terrorists;
   2. The accuracy rate, i.e., the probability that real terrorists will be
identified by NSA;
   3. The misidentification rate, i.e., the probability that innocent
citizens will be misidentified by NSA as terrorists.

No matter how sophisticated and super-duper are NSA's methods for
identifying terrorists, no matter how big and fast are NSA's computers,
NSA's accuracy rate will never be 100% and their misidentification rate will
never be 0%. That fact, plus the extremely low base-rate for terrorists,
means it is logically impossible for mass surveillance to be an effective
way to find terrorists.

I will not put Bayes' computational formula here. It is available in all
elementary statistics books and is on the web should any readers be
interested. But I will compute some conditional probabilities that people
are terrorists given that NSA's system of mass surveillance identifies them
to be terrorists.

The US Census shows that there are about 300 million people living in the
USA.

Suppose that there are 1,000 terrorists there as well, which is probably a
high estimate. The base-rate would be 1 terrorist per 300,000 people. In
percentages, that is .00033%, which is way less than 1%. Suppose that NSA
surveillance has an accuracy rate of .40, which means that 40% of real
terrorists in the USA will be identified by NSA's monitoring of everyone's
email and phone calls. This is probably a high estimate, considering that
terrorists are doing their best to avoid detection. There is no evidence
thus far that NSA has been so successful at finding terrorists. And suppose
NSA's misidentification rate is .0001, which means that .01% of innocent
people will be misidentified as terrorists, at least until they are
investigated, detained and interrogated. Note that .01% of the US population
is 30,000 people. With these suppositions, then the probability that people
are terrorists given that NSA's system of surveillance identifies them as
terrorists is only p=0.0132, which is near zero, very far from one. Ergo,
NSA's surveillance system is useless for finding terrorists.

Suppose that NSA's system is more accurate than .40, let's say, .70, which
means that 70% of terrorists in the USA will be found by mass monitoring of
phone calls and email messages. Then, by Bayes' Theorem, the probability
that a person is a terrorist if targeted by NSA is still only p=0.0228,
which is near zero, far from one, and useless.

Suppose that NSA's system is really, really, really good, really, really
good, with an accuracy rate of .90, and a misidentification rate of .00001,
which means that only 3,000 innocent people are misidentified as terrorists.
With these suppositions, then the probability that people are terrorists
given that NSA's system of surveillance identifies them as terrorists is
only p=0.2308, which is far from one and well below flipping a coin. NSA's
domestic monitoring of everyone's email and phone calls is useless for
finding terrorists.

NSA knows this. Bayes' Theorem is elementary common knowledge. So, why does
NSA spy on Americans knowing it's not possible to find terrorists that way?
Mass surveillance of the entire population is logically sensible only if
there is a higher base-rate. Higher base-rates arise from two lines of
thought, neither of them very nice:

   1. McCarthy-type national paranoia;
   2. political espionage.

The whole NSA domestic spying program will seem to work well, will seem
logical and possible, if you are paranoid. Instead of presuming there are
1,000 terrorists in the USA, presume there are 1 million terrorists.
Americans have gone paranoid before, for example, during the McCarthyism era
of the 1950s. Imagining a million terrorists in America puts the base-rate
at .00333, and now the probability that a person is a terrorist given that
NSA's system identifies them is p=.99, which is near certainty. But only if
you are paranoid. If NSA's surveillance requires a presumption of a million
terrorists, and if in fact there are only 100 or only 10, then a lot of
innocent people are going to be misidentified and confidently mislabeled as
terrorists.

The ratio of real terrorists to innocent people in the prison camps of
Guantanamo, Abu Ghraib, and Kandahar shows that the US is paranoid and is
not bothered by mistaken identifications of innocent people. The ratio of
real terrorists to innocent people on Bush's no-fly lists shows that the
Bush administration is not bothered by mistaken identifications of innocent
Americans.

Also, mass surveillance of the entire population is logically plausible if
NSA's domestic spying is not looking for terrorists, but looking for
something else, something that is not so rare as terrorists. For example,
the May 19 Fox News opinion poll of 900 registered voters found that 30%
dislike the Bush administration so much they want him impeached. If NSA were
monitoring email and phone calls to identify pro-impeachment people, and if
the accuracy rate were .90 and the error rate were .01, then the probability
that people are pro-impeachment given that NSA surveillance system
identified them as such, would be p=.98, which is coming close to certainty
(p=1.00). Mass surveillance by NSA of all Americans' phone calls and emails
would be very effective for domestic political intelligence.

But finding a few terrorists by mass surveillance of the phone calls and
email messages of 300 million Americans is mathematically impossible, and
NSA certainly knows that.

May 26, 2006

Floyd Rudmin [send him mail] is Professor of Social & Community Psychology
at the University of Tromsø in Norway.