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The false positive rate is the whole point of hypothesizing a mad bomber with stringent data practices. If you’re relying on circumstantial web searches for “b

The false positive rate is the whole point of hypothesizing a mad bomber with stringent data practices. If you’re relying on circumstantial web searches for “bomb” or “fertilizer” or “SubUrban Mall map” that correlate with cell phone records of who was there on that day, you’re pulling in farmers, and people who wanted bug bombs to kill spiders, and people who wanted to know how to make a Jaeger Bomb, and people who wanted to know the fastest way to get to Clothing, Ltd. in that mall, etc. And you’re totally missing the nutjob who printed out “bomb-making-101.pdf” a year ago and left his phone at home (or in a friend’s car) when he struck. In an area with 100k nearby people, which is a reasonable search metric since we have cars and malls live in populous areas, if the false positive rate is 1% you now have 1000 people as suspects. What’s your success rate on guessing 1/1000? What tools do you think law enforcement has to further narrow this down?

shadowgovt 6y ago
> What tools do you think law enforcement has to further narrow this down? Further cross-correlation of more data. Have the farmers ever even been to the same town as where the bomb was detonated? Were they there that day? Do they have any apparent motive? What's their alibi? You still have to prove a criminal case beyond a reasonable doubt, so all the points you're raising about alternative explanations for such searches are exactly the things the defense would raise, and why police don't use this data collection as evidence, but to focus the search from 100,000 people to 1,000 people. It's probably worth thinking about it that way: absent this data, police have to assume everyone at the mall might be a suspect, so the pool is 100,000 potential bombers, not 1,000. What's the success rate on guessing 1/100000?

shadowgovt 6y ago

> What tools do you think law enforcement has to further narrow this down? Further cross-correlation of more data. Have the farmers ever even been to the same town as where the bomb was detonated? Were they there that day? Do they have any apparent motive? What's their alibi? You still have to prove a criminal case beyond a reasonable doubt, so all the points you're raising about alternative explanations for such searches are exactly the things the defense would raise, and why police don't use this data collection as evidence, but to focus the search from 100,000 people to 1,000 people. It's probably worth thinking about it that way: absent this data, police have to assume everyone at the mall might be a suspect, so the pool is 100,000 potential bombers, not 1,000. What's the success rate on guessing 1/100000?