• by Joe Mandese  @mp_joemandese, June 19, 2008

Nielsen Wednesday unveiled plans to transition the methods it uses to recruit its paper diary ratings samples, shifting to one that utilizes the addresses of prospective panel households beginning in November, and scrapping its old method of utilizing a "random digital dial" telephone recruiting system.

"This change is based on consideration of three key factors," Nielsen said in a communiqué sent to clients:

* The rapid decline in the coverage of television homes provided by the landline telephone frame. Currently the telephone frame provides, on average, coverage of 75% of households in the diary [markets]; the address based sample frame covers approximately 98% of households.

* The increase in telephone numbers that are separated from the geographic areas in which they were sampled because of number portability, whereby households can "port" their telephone number to a cell phone or use their area code and telephone number in a different part of the country. With [address based sampling] methodology the primary sample unit-the address-is geographically fixed.

* The increase in the percentage of homes which have no landline and are therefore cell phone-only, has led to a corresponding decline in representation among some key demographic groups. This is particularly true in homes where the head of household is age 35 or younger. Federal law prohibits the use of a dialer to reach cell phones without prior permission; however, [address based sampling] provides a means of reaching these individuals, thus improving the representation of the diary sample.