Nielsen to Include Mobile Data Next Season

Series such as NBC's "Grimm" have benefited from alternative viewing

Further expanding measurements of TV ratings, the company cites mounting concerns that not all viewers are being taken into account.

Nielsen plans next week to announce that, beginning with next fall's TV season, it will provide ratings data for shows viewed on smartphones and computer tablets, a source familiar with the plan said Thursday.

The new Nielsen service will be officially announced Tuesday at Advertising Week in New York, according to the source.

Major media companies have long lobbied for Nielsen to measure mobile viewing so that they can negotiate higher advertising rates.

According to a Pew Internet study three months ago, 34 percent of American adults own a tablet -- iPad, Samsung Galaxy Tab, Google Nexus, Kindle Fire, etc. Various other studies indicate as many as 85 percent of tablet users have watched at least some TV on their device.

Also, Nielsen is working on a product for measuring the popularity of shows based on how many fans are tweeting about them. That product could be released much sooner than the mobile ratings service, according to insiders.

In a study Nielsen published Wednesday, 70 percent of tweets sent while watching television are sent during program time while 30 percent are sent during commercial time.