American networks A+E, ABC, AOL, CBS, The CW, Discovery Communications, FOX, NBC, and Univision have all signed on for the test, which will begin in May and run through July.

The pilot for Nielsen Digital Program Ratings will provide overnight audience data, including unique audience, stream counts and reach by age and gender for TV programming viewed online.

“The potential to measure video viewing of specific programmes on linear TV as well as the internet is significant,” said Alan Wurtzel, president of research and media development, NBCUniversal. “It’s an important step toward reaching the ‘holy grail’ of true cross-platform measurement.”