Book of Odds Looks at the 2014 Boston Marathon


This year will be the 118th running of the Boston Marathon, the world's oldest, and the first after the bombings of last year. There will be more runners, about 36,000, than in any year before except the 100th anniversary in 1996 which had over 38,000.

The desire to be part of this historic marathon is so strong that the Boston Athletic Association has had to expand the field through what it calls "an inclusive and virtual model." Runners anywhere may sign up here and run the distance of their choice as part of a "virtual marathon." There will even be 600 participants at Bagram Air Base in Afghanistan, though they will run on the 19th. Echoing JFK's Berlin speech, the BAA Media Guide writes, "On April 21, 2014, we are all Boston Marathoners."

In the immediate aftermath of the tragedy, the response of the city was labeled "Boston Strong:" a calm, determined, and virtually unanimous rejoinder to the horrific events brought so close to home. Boston is the home of Book of Odds, and in memory of those killed and wounded, and in honor of the bravery and solidarity displayed by so many, we use our tools to look at the odds of this horrific attack.


A terrorist attack is a rare event intended by its randomness not to seem so rare. The Global Terrorism Database has documented 113,000 cases of terrorism from 1970-2010. It has three criteria. The act must aim to forward a political or other goal and be outside the traditional definition of warfare by a state actor. The third criterion captures the disturbing essence: "There must be evidence of an intention to coerce, intimidate, or convey some other message to a larger audience (or audiences) than the immediate victims." If an act has nothing to do with the victims and may be said to be intended to speak to anyone in the body politic, its odds of occurring to this person or that are unknowable.

We can say that these events are rare in the U.S. Of all the cases of global terrorism in the GTD database about 2 percent occur in the U.S. and most of these do not lead to death. The odds a terrorist attack in the U.S. will result in a fatality are 1 in 10 (2001-2010). Of course some are more deadly than others, notably 9/11 and Oklahoma City.

Since 9/11, 30 Americans have died of terrorist acts in the U.S., or an average of 3 a year. You are about as likely to be killed in escalator accident in a year, which runs about 2.4 deaths a year. You are about 200,000 times more likely to be killed by heart disease than by a terrorist.

There are two ways of looking at this exposure. One is to consider the likelihood a death will be caused by terrorism. There are about 2.4 million deaths a year in the U.S. Using 2005 as a midpoint, the odds a death in the US will be the result of a terrorist act therefore are 1 in 816,000 (2002-2010). You are 8 times more likely to visit the emergency room for a drinking straw-related accident in a year.

The second, more common way, is in terms of overall population. The odds an American will be killed by a terrorist act are about 1 in 100 million (using 2005's U.S. population). How to put this in perspective? You are more than twice as likely to die from contact with a venomous spider.

(There is a widely reported statistic of 1 in 200 million, which reflects a more selective list of terrorist acts; when working with rare events small changes in event counts lead to big changes in apparent likelihood. This is why vending machine and shark deaths compete each year for apparent likelihood.)

Note that the number of terrorist attacks does not include those thwarted by law enforcement. In 1990 all 31 attempts were successfully completed. By 2011, 5 of 9 recorded attacks were successfully thwarted.

And what about Massachusetts? From 1970 to 2011, and therefore not yet inclusive of the marathon bombing, which would count for one attack, there have been 50 recorded in Massachusetts in the GTD. The odds a global terrorist event will occur in Massachusetts are 1 in 2,260. California and New York have 10 times as many terrorist acts.


The Boston Marathon bombings set the social media ablaze. Twitter had over 20,000,000 tweets on the subject. Researchers such as Kate Starbird of University of Washington analyzed over 10.6 million of these to study how rumors spread and whether they get debunked by the crowd. The most tweeted rumor was the falsehood that an 8-year-old girl had been killed in the attack after running the marathon. This lie was augmented by false photos and massive retweeting. In the data studied there were 95,353 tweets on the subject. About 2,046 were corrections, but the odds a tweet spread the rumor were 1 in 1.05 or 95 percent. It is easy to imagine that this fable of a heroic innocent child slaughtered meaninglessly would prove appealing, as no doubt "blood libel" tales have since Chaucer's day.

A second rumor was political and paranoid. This claimed there had been a "false flag" attack, carried out by the US government to appear like a terrorist act. Again the rumormongers outnumbered the debunkers. Of the 4,005 tweets which could be characterized only 212 offered opposition. Such readings of events are surprisingly common. According to a study published 6 years after the events of 9/11 the odds an adult believes it is very likely that people in the federal government either assisted in the 9/11 attacks or took no action to stop them because they wanted the US to go to war in the Middle East were 1 in 6.2.

A third rumor was a false identification of the bomber with a missing Brown student named Sunil Tripathi. When the first hazy surveillance photos were released some, including a former high school classmate, saw a resemblance between Sunil and Suspect #2. The rumor was addressed by 29,416 tweets and was even picked up by some traditional media outlets. Many tweets claimed that the Boston Police had made this identification. The activity on Reddit, in particular, was criticized in The Atlantic by Alexis C. Madrigal as "vigilantism," the fact-finding phase of lynching. The rumor fell away when the suspects were named by FBI. Nine days after the bombing, the body of Sunil Tripathi, who died weeks before the bombings, was found. What is striking about this rumor is how quickly it spread and then how quickly it died. Between 2:40 AM and 3 AM of the 20th, misinformation went from 40 tweets in ten minutes to 4,690! The correcting tweets were 15 percent of the total and continued long after the rumor died down.


On the Friday morning after the marathon, with one suspect still loose, Massachusetts Governor Deval Patrick asked the people Watertown, Cambridge, Waltham, Newton, and all of Boston "to shelter in place." This request was directed to about 950,000 people or a bit more than 1 in 5 of the Boston Metropolitan Statistical Area. To judge by the unpeopled photos of Harvard Square and Quincy Market, eerie visions of a places with humanity just whisked away, by say, a neutron bomb or The Rapture, most people did their civic duty.

This was a voluntary request, most often associated with epidemics, not martial law, but the distinction seemed to elude many. The America united under the hashtag "prayforBoston" now split into two narratives.

Narrative 1. The one I experienced was of a remarkable feeling of unity and that the "shelter in place" was welcome. It provided a way of helping by removing the chance to hide in plain sight in the hubbub of the streets, and empowered us to search our personal spaces, the ones we know best for anomalies. Indeed it was such a small detail that led to locating the runner in the boat in David Henneberry's backyard. He noticed two paint rollers, which he had put under the edges of the protective covering on his little boat, the Slipaway II, had fallen to the grass. When he could he checked it out and found the bloodstained youth.

There was a surreal and even comic quality to the rushing about of so many branches of law enforcement from so many jurisdictions. Rather than seeming like oppressors, the police were viewed as "first responders," a term applied to civic heroes such as firemen and those who pulled victims from rubble of Ground Zero's poisonous dust.

Dan Riviello, Director of Communications and Media Relations for the Cambridge Police at the time, and the one who sent out the "shelter-in-place" request for Cambridge, told me that the outpouring of love to the police received took them by surprise. The station houses received pizzas, cookies, cards by the gross.

Riviello also said the patterns of "calls for service were drastically lower than on the average day." There were more calls about suspicious objects and sightings related to the search, but if someone had a domestic disturbance on their to-do list, it was deferred to another day. The pattern of 911 calls in Watertown, where the hunt was focused, were different. Seeking to help, citizens dialed in their suspicions. "Watertown would receive 566 calls to 911 on Friday. The day before, there had been 28." according to Hellman and Russell.. And in most cases, when the SWAT teams arrived they were very welcome. "They were kind of begging us -- 'Check the attic, check the basement, check the car,' " said Mike Powell, a police officer and SWAT team member from Malden, as reported by Hellman and Russell.

The sense of a community unwilling to cede its peace of mind to the terrorist outburst expressed itself as calm rather than reflexive anger, and a willingness to express the sense of community in group actions such the lockdown, the ceremonies at Fenway, and the memorials which sprouted up without leadership.


Narrative 2. To some the behavior of Bostonians was seen as sheepish and cowardly as in this comment on the Globe writers' account. The lockdown showed the predisposition of the State to overstep its constitutional bounds. The compliance of the "liberals" (the nicest form of the term in the storehouse of anti-left invective) showed a readiness, perhaps even eagerness to submit to Big Brother.

Ross Douthat, conservative Op-Ed columnist for The New York Times quoted Ha'aretz columnist Chemi Salev:

"This was terrorism's great victory, its spectacular triumph, its abhorrently glorious day in the sun. Never, in the history of violence aimed at innocent civilians, have the lives of so many been disrupted so much by the relatively amateurish actions of so few."

The very response which felt to most of us as common sense, forcing Cain to stand alone, his mark in full evidence, was to Saley, capitulation.

Douthat's reply interestingly is that precisely because the bombers were amateurs and might inspire others, this "no escape" approach might be justified:

"You will be caught, and quickly, because we will move mountains to catch you, up to and including shutting down an entire city to ensure that you stay cornered."

That captures how I felt at the time, and it felt as I were contributing in an aggressive but civilized manner, not cowering in the least. I didn't feel helpless but empowered. I was proud of everyone else, assuming they too had come see this act of civil obedience as a repudiation of the bomber's intent.

Ron Paul, the libertarian, did not see civic pride but the upsetting of the entire civic order, a coup.

"Forced lockdown of a city. Militarized police riding tanks in the streets. Door-to-door armed searches without warrant. Families thrown out of their homes at gunpoint to be searched without probable cause. Businesses forced to close. Transport shut down.

These were not the scenes from a military coup in a far-off banana republic, but rather the scenes just over a week ago in Boston as the United States got a taste of martial law."

There were no actual tanks and no one was forced to comply, but to someone whose orientation is to oppose Leviathan on principle, the behavior of Bostonians and Deval Patrick's lockdown were criminal. About those in lockdown, he asks "What if they wanted to go the grocery store?" Of course they simply went and found the open one, just Deval Patrick went an open local restaurant that day.

Was Ron Paul's instinctive recoil entirely in error? In fairness, there were times when the police behaved insensitively and overstepped the bounds given them. The Boston Globe reported one such incident. A 70-year-old woman in Watertown was terrified by the SWAT team at her door. How did this happen? Dispatcher had a lead at this address, only in Cambridge not Watertown. "It's the fog of war," said Ed Davis, Boston Police Commissioner. I note that this reporter described the SWAT team which so terrified Karolyn Kurkjian Jones as being flanked by a "tank-like vehicle with armor-plated snipers alongside it."

It is unlikely that everyone understood the distinction between "shelter in place" and "martial law," that the former is voluntary and the latter not. Dan Riviello pointed out to me that many businesses sought to get compensation for lost business during the lockdown from the state and were reminded of its voluntary nature.

Even so, the feeling at the time was not of an oppressive state abusing its powers, but that of a battle against the bombers of the Boston Marathon. We could not undo the physical hurt they had caused to innocent people and those who love them. We could rob them of the feeling they had cowed a city. By acting as one, we could deny them any hiding place. We could guarantee they would not escape, and then mourn our dead and hurt with hearts unblemished by futility or hatred. That is in fact what we did.