The main metropolitan markets of the US are now well and truly covered by Nielsen Media Research's controversial Local People Meters as the researcher stuck to its guns and introduced the system to Los Angeles on Friday.

This follows the problematic introduction of the audience measurement service to New York, which roused critics such as the Don't Count Us Out Coalition who deemed it misrepresentative of black and Hispanic audiences. Also, the Media Ratings Council has yet to give its blessing to the new system.

The opposition has maintained its stance, but to no avail. Chicago and San Francisco are next on Nielsen's target list for LPM introduction.

In an attempt to quiet its critics, Nielsen will include paper diary data for the LA July 'sweeps' -- a period during which TV market ratings are made available to advertisers.

Data sourced from:; additional content by WARC staff