Monday, April 25, 2011

Numbers Mean Things

So I saw this headline in The Washington Post:
UN envoy says $5 billion malaria fight has saved several thousand lives in recent years

My first thought was, "$5 billion divided by, let's say 5000 people, that comes out to a million bucks per person saved. A noble result, to be sure, but isn't there a more cost-effective way of achieving the same result?"

Then I read the first paragraph:
UNITED NATIONS — The U.N. chief’s envoy for malaria says a $5 billion campaign has saved several hundred thousand lives in recent years, keeping international efforts on track to virtually end deaths from the mosquito-borne disease by 2015.

(emphasis added) and now the cost per person drops two orders of magnitude, from $1 million to $10,000. Much more reasonable (though it'd still be nice if it were even cheaper).

But I suspect that either the reporter, or someone at AP or WaPo decided that the word "hundred" didn't change the meaning enough to make it worth taking up valuable headline space. I'm sorry, but it does.

Then again, what's two orders of magnitude among friends?

Tuesday, April 12, 2011

The Onion Nails It Again

From The Onion:

'Ghost Hunters' Enjoys Surprising 100% Success Rate

LOS ANGELES—Despite the fact that in all of human history not one person has ever provided definitive empirical evidence of the afterlife, the crew of the second-tier cable network television show Ghost Hunters has shocked statisticians and theologians alike with an incredible and uncanny 100 percent success rate in documenting proof of spiritual presences from beyond the grave. "Well, we have really good equipment," said one cast member, a man in his 30s who sees one or more ghosts each week, without fail, every single time he sets out to do so. "What can I say? We're just really good researchers, I guess." At press time, despite having repeatedly resolved the most central question of human existence, the program is somehow not on the cover of every major newspaper, magazine, and scientific journal in the world.


They got several things right: for one thing, the "really good equipment" used by the ghost hunters picks up phenomena that no other equipment does. That is, there's no independent confirmation that what it's picking up is real. So how do we know that the cause of the reading is a ghost or other otherworldly phenomenon, rather than noise in the equipment, or interference from a nearby radio station, or something like that?

An instrument that detects something that isn't there (false positive) is just as wrong as one that fails to detect something that is there (false negative). If a TSA body scanner finds a knife on you and you aren't carrying one, that's a false-positive. But the TSA inspectors don't know that; all they know is that they've detected a knife. They don't know whether it's a true positive (you're carrying a knife) or a false positive (their equipment misfired). So they use independent tests, such as a patdown (which depends on the knife's tactile properties, rather than its electrical properties) to check. What properties do ghosts have, that would allow us to confirm the reading on one instrument with another?

The other point is that if there's an afterlife, and we can communicate with the dead, there are huge consequences. For one thing, it would affect how we live our lives: what do we need to do to ensure a pleasant afterlife, rather than an unpleasant one?

Or think of the boon to history and anthropology, if historians could interview George Washington's soldiers, or the people who crossed the Bering Strait to colonize Alaska, or even ask William Shakespeare whether he wrote his plays.

Heck, how about subpoenaing the ghost of Ken Lay to question him about his role in the Enron scandal? Or what if a network administrator at company A passes away? Can company B hold a seance and convince his ghost to give up the network passwords?

One idea popular among conspiracy theorists is that Lee Harvey Oswald was murdered so that he wouldn't reveal details about the JFK assassination. But if his ghost is out there somewhere, maybe we could ask him.

In short, if ghosts exist and we can talk to them, why are ghost hunters making millions (let's be generous) on a cable show, rather than making billions or more with an afterlife telecom?

But the Onion said it in a funnier way.