LOS ANGELES -- In a world with hundreds of television channels, figuring out who's watching what is getting harder and harder.
For decades, viewing habits have been tracked through devices attached to TVs and radios in the sample. Thousands of households also kept paper diaries during the crucial television "sweeps" periods in February, May, July and November.
That decidedly low-tech system is about to get a major upgrade.
The two major companies that produce television and radio ratings are testing next-generation technology that would give advertisers the data they need to decide where to spend their billions of dollars.
The most promising is the "portable people meter," a beeper-like device being developed by Arbitron.
It logs programming seen or heard anytime, anywhere by whomever is wearing it.
The gadget requires nothing of participants other than to wear it during the day and place it in a home docking station each night so data can be collected and transmitted to Arbitron.
Better than a diary
The device uses sensitive microphones to pick up codes embedded in television, radio and even streaming Internet broadcasts -- and it includes a motion detector to verify someone is actually wearing it.
"With the portable people meter, we know that you carried it and what it was exposed to," said Thom Mocarsky, a spokesman for Arbitron, which compiles radio ratings.
With diaries, he said, Arbitron has to guess whether a blank page means "they didn't listen to radio or forgot to log in."
Arbitron just completed the first phase of testing, strapping meters on 1,500 participants in Philadelphia. The results were more comprehensive than data collected by current means -- in large part because viewing and listening outside the home was included.
There was also more information on viewing and listening by young males -- a key demographic group for advertisers -- who are notoriously sloppy about recording their habits in diaries, Mocarsky said.
Nielsen Media, which provides television ratings, is watching the tests closely, with an eye toward forming a joint venture with Arbitron to roll out the technology nationally.
Nielsen is testing its own meter to monitor similar embedded codes. Unlike the Arbitron device, the Nielsen meter attaches to individual television sets.
Both systems could become essential as digital television eventually replaces the analog technology now in use. Digital splits channels into several distinct signals carrying program information.
"Digital changes the way television is transmitted, so the channel-based measuring system goes away," said Nielsen spokesman Jack Loftus. "Everyone is going to encoding, and the race is on to see whose code is better."
Advertisers are carefully monitoring both prototypes in their search for more accurate ratings data.
"The (paper) diary is incapable of picking up detailed cable information," said Susan Nathan, senior vice president and director of media knowledge at Universal McCann, part of the Worldwide McCann advertising agency. "There are too many choices. We know the diary is inferior. We have lived with it forever, and it's time to get off it."
Currently, national and local television ratings are measured by Nielsen Media Research using electronic devices supplemented four times a year by paper diaries.
Nationally, 5,000 randomly selected homes are equipped with a meter on each television in the house to log which channels are watched. A second measurement is made by assigning each household member a separate button on the device, which is turned on and off when the person starts and stops watching television.
Detailed demographic statistics for various age groups are gleaned from the data.
The new personal people meters likely won't be used nationally for three to five years