In the wake of last month’s attempted bombing of a U.S. airliner, President Obama has ordered intensified airport screening of passengers from 13 Muslim countries. This move has sparked a healthy public debate about targeted screening in American airports, its effectiveness and its moral ramifications.
Scientifically speaking, there is no question that targeted screening, based on passengers’ personal profiles, is effective, perhaps even necessary, and Israel’s experience with this method is its definitive proof. The art of maximizing chances of detection while minimizing costs of testing has progressed immensely in the latter part of the 20th century; it is now a well-developed science, rich in theorems and algorithms. Some of its conclusions are: 1. Every characteristic of an individual that increases or decreases the likelihood of him/her being a threat should be incorporated in the screening, provided its measurement is not too costly. Ignoring any such characteristic always results in a greater chance of failure. 2. When tests of increasing veracity are available, accompanied with increasing cost, the more accurate test should be applied to individuals who failed the more superficial (and cheaper) tests.
These mathematical and commonsensical principles are practiced routinely in medicine, where patients undergo a sequence of tests of increasing costs and diagnostic power, with hardly any complaints from those who are found healthy, or those found sick. Likewise, a common practice in medical testing is to weigh in every statistically significant clue, from the age of a parent to the color of a cousin’s hair, whenever such clues are deemed “risk factors,” meaning factors that correlate with the disease in question, though not necessarily causally.
However, these statistically proven principles are valid only where statistical science itself is valid, namely, under static conditions, assuming that no change takes place in the population as a result of the screening. In dealing with humans, therefore, we must also reckon with the possibility that the screening strategy in itself, once it is unveiled and practiced, may have an effect on population behavior.
This consideration gives legitimacy to claims that differential screening may have adverse consequences. Here, I do not mean such side effects as irritating Saudi passengers out of investing in the United States, or provoking them into tripling their support of anti-American “charities.”
What we should be concerned about is the effect of statistically based screening on American Muslims, many of whose trust and goodwill we must still win if the war on terror is to be won and if the spirit of America is to be sustained. Explaining to your child why you were picked up again for intense screening at the airport while your friends were ushered through the quick line is not easy; it is, in fact, humiliating, even if you explain to your child that the laws of statistics dictate this selection for the good of society.
Statistically based selection will therefore increase the alienation that American Muslims feel in the post-9/11 era, alienation whose roots were perhaps unavoidable, but whose escalation can still be avoided.
We should hope, therefore, that selective screening based on name, looks and national origin does not extend to American citizens in U.S. airports.
This still leaves unresolved the escalating feelings of alienation and mutual mistrust between the Muslim community and mainstream America, part of which is explicable and part regrettable.
Let us face it, the phenomenon of homegrown terrorism is a real one. A recently published report from Duke University and University of North Carolina lists 139 such cases since 9/11 and notes a “spike” in 2009. Even if one finds solace in the report’s conclusion that this figure is still small compared to terror cases in other countries, no one should be surprised if the phenomenon breeds mistrust in a minority that has allowed it to germinate. However, the main catalysts of this mistrust are not so much incidents like the Fort Hood shooting spree or the North Virginia jihadi plot in Pakistan, but the insincere reaction of prominent Muslim leaders to such incidents and their persistent refusal to introspect and examine whether a causal connection exists between these incidents and the blame-America-first attitude that has been fostering within their community.
Just four days before the “underwear bombing” was foiled in Detroit, the annual convention of the Muslim American Society and the Islamic Circle of North America saw more than 1,000 participants chanting the “America’s war on Islam” mantra, and cheering speakers to the sounds of: [Jews are] “the worst kind of people,” and “It is the duty for all Muslims to liberate all of Palestine from Al Quds to the sea…. It’s all occupied!”
Books by Anwar al-Awlaki, the spiritual mentor of the Fort Hood killer, were sold at the convention, together with those by Sheik Yusuf al-Qaradawi, the revered “scholarly” authorizer of suicide bombing.
The most effective way for American Muslims to restore mutual trust with their non-Muslim neighbors is to assertively replace a leadership that is sending mixed messages to their youngsters, and, most importantly, to stand up to the Saudi-funded clerics who are currently running their religious education, in schools, mosques and prisons.
I cannot think of a more sincere and convincing confidence-building gesture the Muslim community can undertake than sending dozens of Wahhabi-trained imams back to Riyadh, with full salaries, and replacing them with enlightened, American-trained Muslim clerics who share the values and vision of this great country.
Judea Pearl is a professor at UCLA and president of the Daniel Pearl Foundation (danielpearl.org), named after his son. He is a co-editor of “I Am Jewish: Personal Reflections Inspired by the Last Words of Daniel Pearl” (Jewish Lights, 2004), winner of the National Jewish Book Award.
Airport Profiling, Statistics and Mistrust
Judea Pearl
In the wake of last month’s attempted bombing of a U.S. airliner, President Obama has ordered intensified airport screening of passengers from 13 Muslim countries. This move has sparked a healthy public debate about targeted screening in American airports, its effectiveness and its moral ramifications.
Scientifically speaking, there is no question that targeted screening, based on passengers’ personal profiles, is effective, perhaps even necessary, and Israel’s experience with this method is its definitive proof. The art of maximizing chances of detection while minimizing costs of testing has progressed immensely in the latter part of the 20th century; it is now a well-developed science, rich in theorems and algorithms. Some of its conclusions are: 1. Every characteristic of an individual that increases or decreases the likelihood of him/her being a threat should be incorporated in the screening, provided its measurement is not too costly. Ignoring any such characteristic always results in a greater chance of failure. 2. When tests of increasing veracity are available, accompanied with increasing cost, the more accurate test should be applied to individuals who failed the more superficial (and cheaper) tests.
These mathematical and commonsensical principles are practiced routinely in medicine, where patients undergo a sequence of tests of increasing costs and diagnostic power, with hardly any complaints from those who are found healthy, or those found sick. Likewise, a common practice in medical testing is to weigh in every statistically significant clue, from the age of a parent to the color of a cousin’s hair, whenever such clues are deemed “risk factors,” meaning factors that correlate with the disease in question, though not necessarily causally.
However, these statistically proven principles are valid only where statistical science itself is valid, namely, under static conditions, assuming that no change takes place in the population as a result of the screening. In dealing with humans, therefore, we must also reckon with the possibility that the screening strategy in itself, once it is unveiled and practiced, may have an effect on population behavior.
This consideration gives legitimacy to claims that differential screening may have adverse consequences. Here, I do not mean such side effects as irritating Saudi passengers out of investing in the United States, or provoking them into tripling their support of anti-American “charities.”
What we should be concerned about is the effect of statistically based screening on American Muslims, many of whose trust and goodwill we must still win if the war on terror is to be won and if the spirit of America is to be sustained. Explaining to your child why you were picked up again for intense screening at the airport while your friends were ushered through the quick line is not easy; it is, in fact, humiliating, even if you explain to your child that the laws of statistics dictate this selection for the good of society.
Statistically based selection will therefore increase the alienation that American Muslims feel in the post-9/11 era, alienation whose roots were perhaps unavoidable, but whose escalation can still be avoided.
We should hope, therefore, that selective screening based on name, looks and national origin does not extend to American citizens in U.S. airports.
This still leaves unresolved the escalating feelings of alienation and mutual mistrust between the Muslim community and mainstream America, part of which is explicable and part regrettable.
Let us face it, the phenomenon of homegrown terrorism is a real one. A recently published report from Duke University and University of North Carolina lists 139 such cases since 9/11 and notes a “spike” in 2009. Even if one finds solace in the report’s conclusion that this figure is still small compared to terror cases in other countries, no one should be surprised if the phenomenon breeds mistrust in a minority that has allowed it to germinate. However, the main catalysts of this mistrust are not so much incidents like the Fort Hood shooting spree or the North Virginia jihadi plot in Pakistan, but the insincere reaction of prominent Muslim leaders to such incidents and their persistent refusal to introspect and examine whether a causal connection exists between these incidents and the blame-America-first attitude that has been fostering within their community.
Just four days before the “underwear bombing” was foiled in Detroit, the annual convention of the Muslim American Society and the Islamic Circle of North America saw more than 1,000 participants chanting the “America’s war on Islam” mantra, and cheering speakers to the sounds of: [Jews are] “the worst kind of people,” and “It is the duty for all Muslims to liberate all of Palestine from Al Quds to the sea…. It’s all occupied!”
Books by Anwar al-Awlaki, the spiritual mentor of the Fort Hood killer, were sold at the convention, together with those by Sheik Yusuf al-Qaradawi, the revered “scholarly” authorizer of suicide bombing.
The most effective way for American Muslims to restore mutual trust with their non-Muslim neighbors is to assertively replace a leadership that is sending mixed messages to their youngsters, and, most importantly, to stand up to the Saudi-funded clerics who are currently running their religious education, in schools, mosques and prisons.
I cannot think of a more sincere and convincing confidence-building gesture the Muslim community can undertake than sending dozens of Wahhabi-trained imams back to Riyadh, with full salaries, and replacing them with enlightened, American-trained Muslim clerics who share the values and vision of this great country.
Judea Pearl is a professor at UCLA and president of the Daniel Pearl Foundation (danielpearl.org), named after his son. He is a co-editor of “I Am Jewish: Personal Reflections Inspired by the Last Words of Daniel Pearl” (Jewish Lights, 2004), winner of the National Jewish Book Award.
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