Agencies and advertisers have long been concerned about the possible gold-dust slipping through their fingers in the form of unmeasured TV viewing by college kids.

It has always been assumed that the denizens of college campuses are glued to their TV sets for sports coverage and cult programs such as Dr Who and Buffy - and little else. But only anecdotal evidence props up such beliefs.

A new initiative from Nielsen Media Research is about to remedy this longstanding data deficiency. As from next year, the firm will start to include out-of-home viewing at college dorms in its national TV ratings sample.

Extrapolations from a two-year pilot study of college viewing suggest that had student viewing been included in the main dataset, certain shows would enjoy a rise in audience levels.

For example: November 2005 ratings for football would have risen by a full point among college-aged (18-24) men; while among college-aged women ABC would have received a 0.6 rating bump for Grey's Anatomy, while Fox's The OC would enjoy a ratings increase of 0.4.

Overall adult 18-24 viewing levels, Nielsen estimates, could increase between 3% and 12% and might result in a ratings increase of 0.2 to 1.0 for specific programs.

Comments the company's senior vp-planning, policy and analysis Patricia McDonough: "To me, the most surprising fact was that [students] watch as much TV as any other 18-24-year-old."

And that's a lot of TV. During the 2004-05 school year, young adults watched 24.3 hours of TV per week. But this figure excluded college students, the families surveyed being existing members of the Nielsen TV panel.

Data sourced from AdAge (USA); additional content by WARC staff