-By John Consoli, Mediaweek

NEW YORK Nielsen Media Research has issued to its clients a nine-page letter spelling out its plan for the transition to digital-only television broadcasting that goes into effect on Feb. 17, 2009, assuring that "most homes" in its audience ratings sample with TV sets not capable of receiving digital signals will take steps to ensure that they continue to receive TV signals after that date.

According to Nielsen, 11.3 percent of the TV sets in its panels are "unready" to receive digital broadcast signals. Nielsen is requesting that people in the sample with those sets replace them with new sets equipped with digital tuners that will enable them to get over-the-air reception of digital broadcast signals. Or that those people subscribe to cable, so their analog signals can be converted to digital. (Failing that, Nielsen asks that they purchase and connect their sets to government-subsidized, set-top converter boxes.)

Nielsen said its field staff is planning to make a "significant" number of visits to sample households to hook up meters to any new equipment that is purchased. Nielsen has also set a timetable for users in the sample with unready sets to take steps to transition to digital reception.

Nielsen said that none of its field representatives would be allowed to take vacations in January or February of 2009, so that the full staff can concentrate on making sure the conversion goes according to plan.

"Over the next few months, our statistical research department will be reviewing all unready scenarios and potential household actions to determine whether any related changes to our existing editing rules might be warranted on a temporary basis," Nielsen said in a memo to its clients. "The focus will be on those conditions that would cause a home to fall out of tab."

Nielsen said beginning in August, its Data Distributor Management department would begin communicating with local stations regarding their transition plans. Nielsen will then need to take action to make sure it continues to be able to correctly receive and monitor signals to gather information.

Nielsen also plans in December to select a sample of stations that have made the conversion to digital-only signals to see if their signals are adequate for auditing and measuring.

Because the transition is taking place in February, Nielsen will move its sweep measurement period from February 2009 to March 2009 to ensure the most accurate measurement with no glitches.

The Nielsen Co. is the parent of Adweek.