Nielsen has initiated tests with Time Warner Cable, Cablevision Systems and two programmers to try to measure live TV viewing on the cable operators' iPad applications.
The effort is still in "an R&D stage," said Matt O'Grady, Nielsen's executive vice president of media audience measurement.
"Right now, iPad streaming is not having an impact on ratings," O'Grady said. "But we're taking [the project] dead seriously because our clients need to know what the viewing is on tablet and smartphone platforms."
O'Grady declined to identify the two media companies participating in the test.
Time Warner Cable has said its TWCable App for iPad has been downloaded more than 600,000 times since it was released March 15, while Cablevision said last week its Optimum App for iPad topped 200,000 downloads since its early April debut.
Several programmers objected that the MSOs' apps violated distribution agreements, with Viacom pursuing legal action against both TWC and Cablevision with lawsuits asserting breach of contract and copyright infringement. The operators have insisted that providing live TV on iPads -- or any other IP-connected devices -- inside the home is an extension of existing carriage deals.
In part, Viacom and others complained that Nielsen currently is unable to account for viewing on devices such as the iPad.
"Nielsen does not track iPad viewership of entertainment programming," Viacom said in the lawsuit filed against TWC April 7. "This is of tremendous significance because Viacom relies on Nielsen ratings to sell advertising time on its networks, and the greater the audience size, the greater the market value of the advertising time."
Viacom is in negotiations with Time Warner Cable on the TWCable TV app, and the two sides suspended their litigation while they try to reach a compromise.
Last week, Cablevision and Viacom settled the programmer's lawsuit for undisclosed terms.
Nielsen is working with TWC and Cablevision on the viewing measurement project, using a small piece of code on the iPad in conjunction with server-side software. O'Grady said the next step is to launch a "friends and family" measurement test of the iPad apps with Nielsen employees.