It’s clear that teens are controlling more of the household purse strings these days. U.S. News & World Report reported that American kids 12 to 19 spent a staggering $109 billion last year-that’s $63 billion of their own, with the rest coming from their parents-a number that’s risen 38 percent since 1990. The sales will keep rising if predictions that the U.S. teen population will swell to 34.9 million by the year 2010 are true.

How much spending power they have and where they’re directing that money is as difficult to predict as the latest fad. But that hasn’t deterred ad agencies from trying to better understand this influential group.

Many major agencies also have in-house boutique research groups to pool teen data. J. Walter Thompson in Chicago has the J.W. Treehouse, Grey Advertising in New York has Grey 18 and Under, which runs a Web site with monthly surveys of teens on-line, and Saatchi & Saatchi in New York has its Kids Connection, which acts as an agency within an agency.

But perhaps the most exhaustive global overview on teens to date comes from The BrainWaves Group in New York, a division of DMB&B Advertising. The group polled over 25,000 teens in 41 countries as part of its New World Teen Study and discovered a world populated by independent-minded teens who reject tradition in favor of diversity and a culture of their own.

According to Cathy Liepe, senior partner and group planning director at J. Walter Thompson, ‘[teens today] have more money and more skill in using it’ than previous generations had, which she attributes, partially at least, to the fact that more moms are working.

In 1993, 58 percent of mothers in the U.S. found themselves in the work force, a number that Liepe says is projected at 64 percent today. Not only d’es this mean there’s more disposable income in a family, but it also means that teens are having to do a lot of the chores, such as shopping for groceries. ‘It’s almost like they were brought up that way; they developed that skill early on from the generation before them.’

And she adds, because the media has turned kids into such savvy consumers, teens have greater expectations for advertising than anyone who grew up in a household without cable TV. With billboards, postcards, Web site ads and sponsored events all fighting for kids’ attention, she notes, ‘traditional advertising is just one of hundreds of ways of reaching them.’

‘This is a generation where home economics is replaced with consumerism,’ concurs Jana O’Brien, senior vice president and group director of research and planning at Leo Burnett. ‘A lot of these kids have been taught at a very young age that advertising is [intended] to sell you something.’

These savvy consumers expect commercials to include details about the product, but O’Brien hastens to add that a product point needn’t be literal; it could be symbolic and shown through a new graphic. For instance, in research groups for Nintendo, Leo Burnett found that from a mere four-second glimpse at a commercial, a teen can discern everything from the tiniest details of a new 3-D character to a new package color. ‘It’s mind-boggling what they’re able to pick up. They’re incredibly literate.’

With the deluge of information coming from such sources as cable channels to the Internet, it’s difficult or impossible to shelter teens anymore. Of course, that varies around the world. A recent Leo Burnett study found that American parents emphasized independence when they reared their kids, while in Japan, parents worked to shelter their kids as long as possible.

But globally, O’Brien says, the agency is finding a generation that’s big on individualism and diversity. ‘They don’t want to be stereotyped as a group,’ she says. ‘They favor inclusivity and brands that acknowledge different ethnic groups and don’t stereotype. They’re much more aware of different points of view, and much less prone to adopt their parents’ views. This is a group that appreciates honesty, [but] at the same time, they like high-power brands.’

The honest approach comes through in a popular U.S. campaign for Sprite from Lowe & Partners/SMS of New York that uses the tagline, ‘Image is nothing. Thirst is everything. Obey your thirst.’ Brands such as Levi’s and The Gap have also used similar simple approaches in their ads.

But how much money do these kids actually spend and on what? A joint Grey/Scholastic on-line survey found that American tweens-the preteen group in grades six to eight-earned an average of $15.50 a week, while teens earned $68. Combined with weekly allowances of respectively $7 and $14, these kids throw most of their money into purchases that include soft drinks, clothes, fast food, movies and snacks. But there’s a definite variance between the groups: 71 percent of teens purchased their own clothes, compared with only 46 percent of tweens. Indeed, sneakers followed suit, with 47 percent of teens and only 29 percent of tweens buying their own sports sh’es.

Buying influence is another area that’s closely examined. The Grey/Scholastic study also found that kids asked their parents to buy specific brands of things like soft drinks, clothes, sneakers, fast food, cereal, candy, cookies and sports equipment. Other studies indicate that kids even influence the car their parents buy. All of this starts as early as the cereal aisle, where kids learn how to barter for the brand they want.

‘Even when young kids ask for candy, they’ll ask for a specific brand of candy,” says Doreen Massin, vice president of Strategic Services at Grey Advertising. ‘And more often than not, our surveys show that moms will give in to their kids’ specified brand requests for candy or other categories.’

With kids spending more and taking on more of the household purchasing decisions, J. Walter Thompson’s Liepe says categories like packaged goods are finally starting to take notice of teens. Her clients, she says, are beginning to see that teens are a group worth investing in, if they start building brands early on.

What marketers find perhaps the most difficult though is coming up with an ad or a marketing campaign that fits a teen’s definition of ‘cool.’ One safe bet that works, especially in the U.S., says O’Brien, is humor-and not the puffy humor of a 1960s sitcom. These kids grew up laughing at the sarcastic jokes of David Letterman and The Simpsons. What 20 or 30 years ago was perceived as mean-spirited and offensive to people older than 30, she says, is typically a big turn-on for teens.

Liepe believes that J. Walter Thompson’s Brain Freeze campaign launched two years ago for 7-11 Slurpees falls into the cool category. The spot showed a slacker teen lounging in a dirt backyard with flies hovering over him. He takes a long slurp from his ice drink and suddenly lets out a high-pitched shriek from the painful cold head rush. ‘You almost take a flaw in a product, something that gives you an eye-piercing headache,’ Liepe explains, ‘and make it cool to kids. You make that a cultural icon to Slurpees.’

For the last two years, that successful Brain Freeze commercial has been played out in a marketing campaign that includes book covers and T-shirts showing funny pictures of upside-down heads covered in icicles. The MTV Beach House even did a 7-11 event in which contestants slid through a pool of cherry Slurpee. ‘You try to find a way to be a part of their world,’ Liepe says.

The best advice that Leo Burnett’s O’Brien says she gives clients is that ‘cool is not a desired brand strategy. Doing something that’s cool is far better than saying ‘hey, we’re cool.’ ‘