Some 400 km off. I don't know if I can call that a good result. What was anyone supposed to do with this info? Invade Pakistan and run around searching in a 1000km radius? I don't think so.
This reminds me of the "how many piano tuners are there in x" sort of questions. The result can be surprisingly accurate but there are so many underlying assumptions that if any one of them were wrong (which you have no way of knowing in advance) then your result is off by a large amount.
Parachinar is at the border of Afghanistan - Pakistan, closer to Peshawar and Abottabad is closer to Kashmir & Islamabad.
Edit: w.r.t. the 270km radius, 270 km is a big distance for the region. It doesn't seem that big within the context of USA but for the region of Afghanistan/Pakistan, you're quite spread out within that distance and amongst a significant population with similar buildings in cities/towns of the region.
> Our results based on his last know location in 2001 indicate that there is a 98% probability that he is in Kurram, Pakistan, and an 86.6% probability that he is within one of the seven FATAs.
> ... The hypotheses that Osama bin Laden is: (1) located in the Kurram region of Pakistan, (2) located in the city of Parachinar, and (3) at one of the three hypothesized buildings.
all 3 of those were false. Abbotatabad is in a different region, albeit being nearby geographically. The 89.9% accuracy quoted in the Science Insider article (http://news.ycombinator.com/item?id=2510513) is based on the 270km distance from last known location, as shown in figure 2, with the theory that he is most likely to stay close to that point.
If you add what we know now about Bin Laden's courier - obtained by the intelligence community but naturally kept secret until now - their methodology would have nailed it down to just a couple of buildings in Abbottabad. That's very impressive IMHO.
