Monday, July 22, 2013

Guest Reviewer Jeff on "The Signal and the Noise" ------- Part 4

Part 4 - Predicting terrorist attacks

Silver ends his book by taking on a daunting task: how to forecast a terrorist attack. This entails all of the content and insight of the previous 411 pages of the book (there are a fascinating 75 pages of detailed footnotes at the end that are worth reading by themselves). Here again we find ourselves sorting signal from noise. Though Silver doesn’t use the expression, he documents a lot of after-the-fact armchair-quarterbacking that took place following the 9/11 attack.

In hindsight, there was also a lot of signal out there about the impending Japanese attack on Pearl Harbor on December 7, 1941 - hindsight is always 20/20. The mind-set of the American forces in 1941 was that there was probably trouble brewing in the Pacific. Japan was invading China and Korea, and had allied itself with the German-Italian fascist Axis. However, there had not been an attack on the US since 1812, and a sneak attack was just not in anyone’s mind. Instead, the racism of the day led planners to expect sabotage by the large Japanese population on the Hawaiian islands (people who were slightly newer assimilating Americans - and who had left Japan for a reason). To that end, the US military put their battleships and aircraft close together to make them easier to guard. What a gift to Admiral Yamamoto! Incidentally, my dad saw the writing on the wall on December 7th, and enlisted a week later as a soberly-thought-out means to protect himself from becoming sacrificial infantry in the conflagration that was certainly to come. On that same day as the Pearl Harbor attack, Donald Rumsfeld (the Secretary of Defense during 9/11 and its aftermath) was an 8-year-old boy listening to a broadcast of his beloved Chicago Cubs. The game was interrupted with the news bulletin of the sneak attack, which left a life-long impression on him. It turns out in hindsight that there were an extraordinary number of warnings out there - too many to include in this review.

Similarly, the official 9/11 commission providing the hindsight for the attacks on the Twin Towers found an extraordinary number of warnings before the attack. They were all lost in the noise. The commission correctly identified a number of systemic problems, including the distrust and lack of data-sharing among agencies, and these have largely been corrected. However, the over-reaction to 9/11 has led to a hugely expensive and overblown airport security apparatus euphemistically called the Transportation Security Administration. I could be mistaken in this, but I believe that it has not prevented a single aircraft-based attack since its inception (however, airline passengers have). The response to 9/11 has also led to the extraordinary intrusiveness of data-gatherers like the FBI and the NSA, exposed recently by Edward Snowden. You see, one of the directions people reflexively charge, when trying to predict something important to them, is to gather even more data. In almost all cases this translates to vastly more noise.

In both cases these horrific events were not detected in time. The American Airlines Flight 93, aimed apparently at the White House, was brought down by fearless passengers whose flight departure had been delayed by 45 minutes, so they had time to learn what was going on - and the courage to do something about it.

The common denominator between these two attacks was the “unknown unknowns” of the famous Rumsfeld quote. We just didn’t know that there was an unanticipated unknown out there, and fell into the trap of assuming an unknown was an unlikelihood. It was NOT an unknown to the passengers on AA 93.
However, Silver does a cold-blooded analysis of the data, and shows several important things about 9/11 attack precursors:

1a. The number of suicide attacks worldwide had been growing for the previous 30 years at an accelerating rate. Terrorist attacks against the West had started in 1979 - Silver correlates this with the Iranian revolution. Irrespective of cause, the power law curve would say such an attack was inevitable.

1b. However, the real “origin event” behind this increase is something that Nate Silver completely misses.  This was the take-over of the Grand Mosque in Makkah by ultra-conservative Wahhabis, rebelling against the obscene corruption of the al-Saud family who ruled Saudi Arabia. To keep their position on top of the Arabian Peninsula Fount of Eternal Wealth, the Saudi royal family made a momentous strategic decision: we will be more Wahabbi than them - we will get ahead of the curve. This included the Kingdom paying to export Wahabbism. The result is Salafism (mistakenly called “jihadism” in America). Saudi money paid for Madrasas (schools for boys of poor families) that taught no useful life-skills in places like Pakistan and Somalia and Indonesia. Instead, they had boys memorize the Qu’ran and preached the most ultra-conservative and Christian-hating form of Islam to them. In effect, they exported and gave us the Islamic radicalism that lead to 9/11. In 1979 the dominant form of Islam in Pakistan was Sufism - a gentle, mystical form of Islam. Today Sufism bears the brunt (along with Shi’ites and Hazaris and women) of the murderous hatred and violence of the Salafists. Bin Laden, in retrospect, was just a minor side effect of that terrible 1979 Saudi strategic mistake.

Can we make use of this better understanding of what created the Salafist system? I think we can, and I’m aware that people have bent a lot of thought to it in the Intelligence community.

2. The number of terrorist attacks and their kill-rate follow a power curve - just like earthquakes. Plotted on a linear graph of frequency of attacks vs fatalities, there seems to be no pattern. However, plot these on a log-log curve, and the 9/11 attack can be seen to be inevitable.

Sure, there was signal in the vast ocean of international electronic noise, but we were blinded by what Silver summarizes this way:

“There is a tendency in our planning to confuse the unfamiliar with the improbable....When a possibility is unfamiliar to us, we do not even think about it.... In medicine this is called anosognosia: part of the physiology of the condition (for instance Alzheimer’s) prevents the patient from recognizing that they have the condition.”

In hindsight, the warning signs were there in abundance. But in hindsight, we didn’t have a chance to do anything about it.


In summary, this is a wonderful book. It’s fun to read, and Nate Silver misses little and teaches a lot. It has crystallized areas in my own understanding that previously were somewhat amorphous. It shows why ALL forecasting can only be probabilistic - and how to wrap our heads round this. The book helps me understand my own data better as a professional scientist - or more to the point, it has helped me to understand how to interpret my data more correctly.

I must conclude with a few favorite quotes from the book:

“A conspiracy theory might be thought of as the laziest form of signal analysis. As the Harvard professor H.L. Gates says, ‘Conspiracy theories are an irresistible labor-saving device in the face of complexity.’” (...used as a crutch by mentally lazy people, I would add. ) (p. 417)

“But the number of meaningful relationships in the data - those that speak to causality rather than correlation and testify to how the world really works - is orders of magnitude smaller <than the burgeoning data out there>. Nor is it likely to be increasing at nearly so fast a rate as the information itself; there isn’t any more truth in the world than there was before the Internet or the printing press. Most of the data <are> just noise, as most of the universe is filled with empty space.” (P. 250)

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