NEW YORK: Nielsen will start releasing US out-of-home TV viewing figures recorded in places such as hotels, bars and offices from September.

In partnership with California-based Integrated Media Measurement, which has previously worked with a number of broadcasters on similar projects, the company will calculate its figures using a special cellphone system able to recognise programs by sound alone.

Some 3,000 participants have already been recruited in six cities - including Chicago, New York and Los Angeles - and Nielsen is to recruit a further 1,700.

It will initially sell the combined and individual city ratings as an extra service, but plans to combine them with its current at-home ratings in the future.

Sara Erichson, executive vice president for client services at Nielsen Media Research North American, said: "Nielsen has a mandate to follow the video wherever it goes.

"A lot of where video is going is outside the home."

Among the channels tipped to benefit is ESPN, as a considerable amount of sports viewing is thought to occur out-of-home.

CNN and CBS have also being pushing for the introduction of similar technology for some time, arguing that much of their output is seen in places like airports and offices.

Data sourced from New York Times; additional content by WARC staff