For decades the radio industry has relied on select listeners to journal their radio listening on paper and submit these diaries for compilation into ratings that helped amongst other things to determine advertising rates. I've had occasion to participate in these surveys myself as recent as a couple of years ago. The industry seems to be catching up with technology now with new measuring devices called Portable People Meters, or PPMs. The PPM records inaudible signals that identify what radio station you are listening to, when you listened, and for how long. "Sometimes what you listen to isn't always what you recall three days later," said Greg Strassell, senior vice president of programming for CBS Radio. "Rather than guessing how listeners were listening, this is actual info we can use. This is why program directors are very excited." This seems like a much more accurate measure and one that is less painful for the participants! LA Times story here.
