Okay, I get the whole Freakonomics thing, but c’mon. This is the dumbest idea I’ve ever heard :

But with a fine of just $50 for the first offense, the law doesn’t provide much financial incentive to pick up after your dog. Nor does it seem to be vigorously enforced. Let’s pretend that 99 percent of all dog owners do obey the law. That still leaves 10,000 dogs whose poop is left in public spaces each day. Over the last year, the city ticketed only 471 dog-waste violations, which suggests that the typical offender stands a roughly 1-in-8,000 chance of getting a ticket.
. . .
Here’s an idea: DNA sampling. During the licensing procedure, every dog will have to provide a sample of saliva or blood to establish a DNA file. Then, whenever a pile of poop is found on the sidewalk, a sample can be taken to establish the offender’s DNA. (Because stomachs and intestinal walls shed so many cells, poop is in fact a robust DNA source; during a murder trial in Indiana in 2002, the defendant was convicted in large part because the dog poop in his sneaker tread linked him to the scene of the crime.) Once the fecal DNA is matched to a given dog’s DNA file, the dog’s owner will be mailed a ticket. It might cost about $30 million to establish a DNA sample for all the dogs of New York. If people stop violating the law, then New York has spent $30 million for cleaner streets; if not, the $30 million is seed money for a new revenue stream.

Unfortunately, there’s a big drawback to this plan. In order to match a pile of poop with its source, you will need to have every dog’s DNA on file – and in 2003, the most recent year on record, only 102,004 dogs in New York were licensed. Even though a license is legally required, costs a mere $8.50 a year and can be easily obtained by mail, most dog owners ignore the law, and with good reason: last year, only 68 summonses were issued in New York City for unlicensed dogs. So even if the DNA plan were enacted today, most offenders would still go unpunished. In fact, it stands to reason that the typical licensed dog is less likely to offend than the typical unlicensed dog, since the sort of owner who is responsible enough to license his dog is also most likely responsible enough to clean up after it.

How, then, to get all of New York’s dogs licensed? Instead of charging even a nominal fee, the city may want to pay people to license their dogs. And then, instead of treating the licensing law as optional, enforce it for real. Setting up random street checks for dog licenses may offend some New Yorkers, but it certainly dovetails nicely with the Giuliani-era “broken windows” approach to low-level crime.

So, once you get over the initial costs of setting up the dog shit crime lab and paying every dog owner to register their dogs, all you have to pay for is for the extra cops to act as canine brownshirts (no pun intended) to shake down doggies for their papers and an enormous bureaucracy to collect and DNA test as much shit as they can scoop up. Doing a quick Google search, it looks like a cheap consumer DNA test is around $200. Even if you take into account that the price would be reduced due to volume of tests and the assumption that the government would set up its own testing facility, you’ve gotta wonder how many turds they’ll need to test for every $50 ticket.

What’s worse is that the DNA argument is preceded by this incredibly misguided analogy :

Might there be a way to get rid of dog poop without getting rid of the dogs? It might help for a moment to think of a dog as if it were a gun. Using laws to eliminate guns has proved extremely difficult. A given gun lasts a very long time, and as with dogs, guns are widely loved. But getting rid of guns should never have been the point of gun control; the point, rather, ought to be getting rid of the misuse of guns – that is, the use of guns in crimes. Consequently, the most successful policies are those that directly punish misuse, like mandatory prison sentences for any crime involving a gun. In California and elsewhere, such measures have substantially reduced gun crime.

This conveniently omits the fact that more analogous ideas such as mandatory DNA testing for capital crimes and a ballistics fingerprint database have been very controversial proposals. Unless they’re thinking about a three-strikes law for dog crap, they’d probably be better off dropping this bit before pursuing this pipe dream any further.

And before anyone thinks I’m not seeing the humor in a bit of Swiftian self-satire, here’s how their “no, we’re serious” conclusion :

Before you dismiss the entire dog-DNA idea as idiotic – which, frankly, we were about to do the moment it popped into our heads – consider this: it turns out that civic leaders in Vienna and Dresden have recently floated the same idea. (Indeed, one Vienna politician cited Mayor Giuliani as his inspiration.) Closer to home, an eighth-grade girl in Hoboken, N.J., has also proposed the DNA solution.

That’s right. We should take this proposal seriously because it’s supported by a 12-year-old girl.