Best We Can

Nothing gets people talking like a shared grievance. Misery, as everyone knows, loves company, and anyone who has ever been laid off or evicted, or even had to cut back on groceries has found quick solace in the similar complaints of their friends and neighbors. Stories of the run-down neighborhood that rose from the ashes when residents banded together to fight crime, or repair abandoned homes for resale, or convert empty lots into gardens are far from uncommon. Indeed, the hard-knock neighborhood lifting itself up through a communal sharing of the burden is an archetype of urban development.

There's a lot to be worried about these days. There's a lot to complain about. But we can believe that things are going to get better; in fact, it's doubtful that they can until we do.

The Project for Public Spaces published an article on their most recent newsletter entitled How Your Community Can Thrive-- Even in Tough Times, that made the blunt but wisely-worded case that cities, now more than ever, have to use what they've got. As financial markets collapse and leave perpetually cash-strapped city governments scraping by or knee-deep in red ink, expensive programs, high-profile redevelopments, and frivolous policies can no longer be relied upon to distract any attention from the most deeply-seated problems that face their communities. "What They've Got," for cities, is suddenly much less than it was.

Jonah Lehrer, speaking recently about the late Studs Terkel's book Hard Times, made this important point: "While a depression or steep recession is a terrible thing, it does lead to a few less Rolexes. And if the Terkel interviews are any indication, it was that diminished sense of disparity - the fact that everyone was going without - that made the time bearable." One thing that cities have got, today, is an economic mess on their hands; luckily, just about anything can be seen as an opportunity in the right light, and Lehrer's comments suggest a critical urban asset that should not be overlooked in these hard times: shared struggle.

A note to all those people who have been worrying about the collapse of traditional community structure in urban neighborhoods: now is your chance to change the course. It is somewhat rare that an economic crisis hits so hard that even the relatively wealthy are genuinely hurting; at the risk of sounding overly opportunistic, it is the depth of this recession that could provide a rare chance to get neighbors talking to neighbors, and sharing the burden of hard times in the community. As stated at the outset of this post, nothing gets people talking like a shared grievance. If awkwardness or ignorance have ever been reasons for avoiding a chat with the folks next door or down the hall, everyone now has something to talk about, to share, and to help each other with.

The effect that the current crash (we can call it that, right?) is having on our economic system will undoubtedly be extreme. The fundamental building blocks of our society will change, whether we like it or not. But if you're smart, you'll make what you can of hard times, and get to know what's going on in the lives of the people around you. When something shatters The Way Things Work like we're seeing them shattered today, there are small but invaluable shards of opportunity scattered all around. To some, it might look like a mess; to the wise, it is the start of a newer Way that will be stronger than what came before it.

(Photos from Wooster Collective and Flickr user Scott Haefner. The original full-sized color version can be viewed by clicking the photo.)

The Paradox of the False Positive

An excerpt from Cory Doctorow's latest book, Little Brother:

If you ever decide to do something as stupid as build an automatic terrorism detector, here's a math lesson you need to learn first. It's called "the paradox of the false positive," and it's a doozy.

Say you have a new disease, called Super-AIDS. Only one in a million people gets Super-AIDS. You develop a test for Super-AIDS that's 99 percent accurate. I mean, 99 percent of the time, it gives the correct result -- true if the subject is infected, and false if the subject is healthy. You give the test to a million people.

One in a million people have Super-AIDS. One in a hundred people that you test will generate a "false positive" -- the test will say he has Super-AIDS even though he doesn't. That's what "99 percent accurate" means: one percent wrong.

What's one percent of one million?

1,000,000/100 = 10,000

One in a million people has Super-AIDS. If you test a million random people, you'll probably only find one case of real Super-AIDS. But your test won't identify *one* person as having Super-AIDS. It will identify *10,000* people as having it.

Your 99 percent accurate test will perform with 99.99 percent *inaccuracy*.

That's the paradox of the false positive. When you try to find something really rare, your test's accuracy has to match the rarity of the thing you're looking for. If you're trying to point at a single pixel on your screen, a sharp pencil is a good pointer: the pencil-tip is a lot smaller (more accurate) than the pixels. But a pencil-tip is no good at pointing at a single *atom* in your screen. For that, you need a pointer -- a test -- that's one atom wide or less at the tip.

This is the paradox of the false positive, and here's how it applies to terrorism:

Terrorists are really rare. In a city of twenty million like New York, there might be one or two terrorists. Maybe ten of them at the outside. 10/20,000,000 = 0.00005 percent. One twenty-thousandth of a percent.

That's pretty rare all right. Now, say you've got some software that can sift through all the bank-records, or toll-pass records, or public transit records, or phone-call records in the city and catch terrorists 99 percent of the time.

In a pool of twenty million people, a 99 percent accurate test will identify two hundred thousand people as being terrorists. But only ten of them are terrorists. To catch ten bad guys, you have to haul in and investigate two hundred thousand innocent people.

Guess what? Terrorism tests aren't anywhere *close* to 99 percent accurate. More like 60 percent accurate. Even 40 percent accurate, sometimes.

What this all meant was that the Department of Homeland Security had set itself up to fail badly. They were trying to spot incredibly rare events -- a person is a terrorist -- with inaccurate systems

.

DHS, in Doctorow's skillfully-written book (full disclosre: I'm a long-time fan) has taken over San Francisco after a pretty horrific terrorist attack, and implemented a security net so obnoxious that everyone is a suspect, turning the "innocent until proven guilty" maxim fundamental to the US justice system on its ear in the name of "protecting" the very citizens it interrogates on every corner.

As if we needed a reminder, the recent Mumbai attacks have thrust the extraordinarily rare specter of the large-scale, well-coordinated urban terror strike back into the public spotlight. Doctorow's greatest strength has always been his ability to make the future feel incredibly near; it is not even remotely difficult to imagine a scenario like the one described in LIttle Brother playing out were another major attack to strike a US city. Almost as frightening than the idea of an actual attack (or more frightening, depending on who you talk to) is the idea of what might come after. Imagine a massive citizen-tracking web, to put London's CCTV to shame, layered on top of the already overanxious contemporary cityscape, and consider the paradox of the false positive. Not pretty.

Little Brother is available for free download under Creative Commons licence right here.