NEW YORK -- Six television sets line the wall at a Manhattan health club, where patrons on treadmills one afternoon choose between CNN, CNBC or soap operas -- or simply stare at their reflections in a mirror.
In the eyes of the television industry, these viewers don't exist.
Neither do the people who watch Monday Night Football in their favorite bar, college students who turn on David Letterman in their dorms, or travelers who check the morning news before leaving a hotel room.
Nobody really knows how much TV people watch outside of the home. It's an odd lapse for a business with an entire financial structure based upon measuring viewers, coming at a time when TVs are popping up in places they've never been seen before.
Executives at the financial news network CNBC believe thousands of their viewers are being overlooked and are pleading with Nielsen Media Research to find a way to measure out-of-home viewing.
"I think Nielsen is as frustrated about this as other people are, and it's not just CNBC," said Bill Bolster, president of CNBC.
Nielsen says it will count this audience on a regular basis if someone pays for it, but no one is writing any checks yet.
The television networks pay the bulk of the weekly Nielsen ratings of how many people watch TV, with advertisers and their clients paying smaller amounts. These weekly estimates are the industry's Bible, with shows living and dying based on what they say.
Long a staple in hotel rooms and the corner bar, television sets are appearing frequently in offices, gyms and airports. Some top-line hotels have even installed sets in elevators.
Nielsen estimates that 25.7 million adults watch some TV outside of their homes each week, up from 23 million in 1994.
"The out-of-home aspect of viewing is growing and will continue to grow," said David Poltrack, chief researcher at CBS. "Eventually, it's going to have to be measured."
Different networks have different reasons for wanting these viewers counted. CBS is the top-rated network in daytime programming, and is convinced a large number of women take a break in their offices to watch soap operas.
ABC believes many men watch Monday Night Football in bars, and even Nielsen concedes that counting these viewers would likely add a full rating point to that telecast each week.
CNN estimates it is available in 1 million hotel rooms, and believes that many travelers tune in to catch up on the news, particularly in the morning.
CNBC's average audience at any given moment is 300,000 people, according to Nielsen. Mr. Bolster estimates an additional 120,000 people are watching in offices, health clubs, restaurants and other places not measured by Nielsen.
Since ad rates are based upon the number of viewers, Mr. Bolster said this costs CNBC between $50 million and $75 million per year.