Most PSA's run between midnight and 6 a.m., according to the study unveiled last month by the Kaiser Family Foundation, an independent philanthropy concerned with health issues.
Kaiser tracked use of public service ads by Walt Disney Co.'s ABC, Viacom's CBS, News Corp.'s Fox and General Electric Co.'s NBC, along with five cable channels and Univision, from Feb. 28 to May 14, 2000.
According to the study, during prime time the four major networks donated five seconds an hour. That drops to four seconds when PSA's that the networks are required to run to get media buys from the White House Office of National Drug Control policy are excluded. (The drug office requires broadcasters to match each paid ad it buys with a free PSA in similar programming.) Cable networks donated about eight seconds an hour during prime time.
Vicky Rideout, a foundation VP, said the foundation didn't take a position on the numbers its study revealed, but said the study may provide insight for policy-makers and groups seeking to get their messages across. "Non-profits have to look at the reality of what airs before producing ads. They have to look at the costs and whether they need to partner [with a network] to get on the air," Ms. Rideout said.
The study said that network-sponsored PSA's represent a quarter of donated announcements on the four major broadcast networks, and that more than a third of announcements are 20 seconds or shorter.