It used to be said that all you needed to be a good youth planner or researcher was a copy of The Face. This is sadly no longer the case. Now you need a copy of Sugar as well. And perhaps Now or Heat. I'm joking, but only just.

Every year, brand owners shell out a fortune for insights into "youth" which they could pick up at their local newsagent or by hanging out at the Meadowhall shopping centre for half a day. Youth is the centre of attention for so many programme-makers, journalists and academics that a big youth marketing study seems hugely gratuitous.

Youth is one of the most over-researched areas of marketing (and one of the last remaining advertising gravy trains) because thirty- and fourtysomething marketing and ad people are obsessed with it and convinced there's something weird going on that they don't understand. And lots of talented and funky researchers make a decent living by preserving the mystery around youth and coming up with a new paradigm shift every year - a paradigm shift poised convincingly between "teenagers, same today as they've ever been" and "you won't believe what the kids are up to these days, they've got mobile phones and all sorts". But they wrap it up in the arcane language of semiotics and ethnography, throw in some edgy language cribbed from Grange Hill and neatly obscure the banality of their observations.

Brand people are fascinated with this stuff because we can all relate to it personally. Not everyone's been a 35- to 45-year-old housewife, or an AB luxury car purchaser, but everyone's been young. So there's always this generational intrigue built into the process. We can't help asking ourselves why kids today are so apathetic, or not apathetic enough, compared to how we were at their age (when the music was much better, the drugs more interesting and it all really seemed to matter, you know?).

It makes for one of the most interesting presentations of the year, full of debate and personal reflection - even if they could also have been generated by a few copies of Ministry and an hour or so at a local school.

The really pernicious thing about these studies is that being able to subscribe to them stops you going out and doing the research yourself. There's really no substitute for that. Going out and actually meeting some young folk is a thousand times cheaper and a thousand times more effective than any amount of PowerPoint.

In our experience, what young people want from brands is that we do our jobs and leave them alone. We should create fascinating new products, exhilarating new ads and surprising new ideas by using our imagination and daring. Not by continually asking them what they want, or what they're doing or what they're watching. They're looking to brands for new ideas, not knock-offs of the ideas they've already got. The only thing that they could possibly be interested in now is something they've never even thought of.

Russell Davies is planning director at Wieden & Kennedy

russelld@wk.com