At first, some readers thought Science had made it sound like Gillespie's team had said two years ago that there was an 88.9 percent likelihood that Osama bin Laden would be hiding out in Abbottabad, Pakistan.
In fact, Gillespie tells us, the work had predicted that it was likely bin Laden would be in Pakistan, in a city, and not too far from the border with Afghanistan and that nation's Tora Bora mountains — where he had last been seen, in 2001. But in the paper they wrote, the professors settled on Parachinar, Pakistan, as the most likely location for the world's most famous terrorist. It's closer to Afghanistan than Abbottabad.
As Korva noted earlier, Gillespie and Agnew used the theory of "island biogeography" to predict where bin Laden might be. The theory is that, as Science wrote, "a species on a large island is much less likely to go extinct following a catastrophic event than a species on a small one."
Or: someone like bin Laden would be much more likely to survive in an urban, populated area where he could blend in than in a sparsely populated region where a tall, bearded man with guards might stick out. And he wasn't likely to have gone too far from his last known location because traveling would expose him to dangers.
They then took their work further, to speculate on the type of home bin Laden would need — and came remarkably close to the high-walled, multi-building compound where he was found.
Finally, they drew rings extending out from Tora Bora, and based on their models decided just how likely it was that bin Laden might be in a city on or near one of those rings. Parachinar lands at about the 98 percent mark. Abbottabad, it turns out, lands around 88.9 percent.
To further complicate things, they pretty much dismissed the chances of bin Laden being in Afghanistan, even though the rings obviously included cities there. "The U.S. military is there," Gillespie says. "They've got some really smart people in Afghanistan." Bin Laden would want to avoid them.
Gillespie concedes that even he hadn't totally bought into the conclusion that was reached in the paper. "My own personal hunch was he'd be in Baluchistan," a region of of Pakistan well to the south and west of where he ended up, and where bin Laden could have drawn on support from the Taliban and Pashtun tribes, he says.