It was Self-Abuse Week again in the news trade, after so many of the media's political hacks got Iowa so wrong.

It may be impossible to predict elections, but the one thing you can predict with perfect certainty is that on the morning after a surprising vote, the media will declare themselves the big losers, with a torrent of shocked-shocked stories along the lines of "Pundits Got It Wrong." The Washington Post's Web site ran that very headline on its front page Tuesday morning, over a hot-off-the-template piece by media reporter Howard Kurtz.

Crystal Balls Not Good at Predicting Future! It was big news in the 17th century, and it's still playing to raves today.

Political prognostications are just one feature—and, to my mind, among the least interesting—of a much broader media genre: the trend story. Trendspotting has always been a core media skill, of course, but in recent decades it's been trending upward, as the practitioners of this art like to say. ("Young Voters Said to Be Trending Toward Bush," declared a headline on the Drudge Report in the wild hours after the Iowa shock, when you could hear a thousand trends reversing themselves, like those garbage trucks that beep when they go backward.)

The modern media have figured out all kinds of creative ways to detect and package trends. The Dean-on-Fire story that played so huge in the weeks before the Iowa vote is just the political version of a story line that recurs constantly in every corner of the media universe, about some hot new trend that's sweeping the region, the nation, the globe. It's breathtaking how many trends we consume every day, served up by the trendaholic media.

The Wall Street Journal is especially skilled at combing the landscape for hidden trends, proto-trends and not-really-quite-trends-but-what-the-heck, and turning them into delightful features that you can retail at dinner parties. There was a memorable one last year about "nudism's growing popularity," with nude vacations and nudist housing developments simply taking off. Just last week, The Journal had a fun front-pager about how non-Jewish kids are having bar and bat mitzvah parties, just to keep up with their Jewish friends.

Like many cultural trend stories, this one had a decidedly anecdotal feel. It opened with a story about a girl in Texas who had a traditional Jewish coming-of-age party, though she and her family are Methodists. Then came the trend graf: "A number of kids about to turn 13 who aren't Jewish are bugging their parents for parties that resemble those held following bar mitzvah ceremonies. In some affluent communities, parents line up the same entertainment and book the same party places. If they don't dance the traditional Jewish hora, they at least manage a tarantella or an Irish jig."

The first time I read this passage, the nice imagery at the end was so vivid I overlooked the vagueness of "a number of kids" at the beginning. What number? Only three specific kids are mentioned in the story, but a few party companies told The Journal they were booking more of these events than in previous years, including one outfit that claimed it did "more than a dozen" last year. So are gentiles everywhere throwing these bashes for their kids? Nah. Is it a trend? Maybe, in a small way. No question it will help those party planners drum up new business.

A trend story doesn't have to be new to make a splash. Some are hardy perennials. Not a year goes by when the media don't report that teenagers are having sex earlier, except when the trend is that they're having it later, as one recent spate of trend stories claimed. Several years ago, The Washington Post uncovered a stunning teen-sex trend: "Eager to avoid pregnancy and hold on to virginity, an increasing number of teenagers are engaging in oral sex, according to school and health officials." Good thing previous generations of teens didn't discover that, huh?

Trends rely heavily on data, and one of the reasons trend journalism has taken off is we're awash in data of all sorts—scientific data, census data, polling data, barcode data; data from industry groups, from academic studies, and from professional trendspotters such as the oft-quoted Faith Popcorn. Give a journalist a bunch of data, and they can generally identify a trend and find a source who gives good quote. I've done it myself; it's easier than it looks.

Is the trend trend dangerous? Sometimes. The stock market mania of the 1990s, pumped by a credulous media, was one trend that hurt a lot of people. And what ever happened to this winter's deadly flu?

Many trends are real, of course. When one proves not to be, the journalists and outlets that promoted it pay a price in credibility, as we saw this week when the dead-wrong political pundits received their citations from the increasingly vigilant media police.

I kind of like trend stories, not so much for what they say on the surface, but what's just beneath. They play straight to our hopes and fears and, even when they're shaky, wind up telling us a lot about who we are.

My current favorite is the comeback of bedbugs. Have you heard? It's a "growing problem" that's been reported in dozens of media outlets over the last year or so, in both Europe and North America. This is a trend story with everything: scientific data, creepy anecdotes galore, a recent lawsuit against the Motel 6 chain, and a nursery-rhyme ditty (Good night, sleep tight, etc.) tailor-made for cute headlines. Yup, those nasty critters are biting again, and this being a trend, so, inevitably, will we.

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