In this week’s Programming To Win column, Richard Harker takes another look at the world of PPM. Harker examines the specific technology behind the meters’ ability to record listening, and discusses how a radio’s volume and the movement of a panelist wearing the meter play key roles in PPM ratings data.
Richard Harker
By Richard Harker
PPM meters are unquestionably the most sophisticated and complicated audience measurement tool ever created. It took nearly two decades of research and development to bring PPM to market.
It is therefore ironic that the accuracy of PPM ultimately depends on something as old as radio itself: A plain old analog microphone.
The PPM encoder in your audio chain adds a unique signature to your audio, a burst of audio tones that distinguishes your station from every other station. And your station only gets credit if the analog microphone in the meter picks up the code (along with a time stamp and a few other bits of data).
Yes, in this increasingly digital world, PPM is essentially an analog device at its core.
Arbitron tells us that if a station is loud enough to hear, the code is loud enough to register. That also means that if the meter is somewhere where the station code is not loud enough to be reliably detected, no credit will be given.
So the best chance for getting credit is if the meter is worn out in the open, preferably as high as possible. In fact, early tests of the meter were done with the meter worn around a participant’s neck like a pendant (think of Mr. T). Arbitron also tested the meter held in a mesh pouch worn on the hip.
It is unlikely that many current PPM panelists are wearing their meter on a chain around their neck or in a mesh pouch, which begs the question where people are wearing their meters.
Arbitron photos typically show the meter worn on a belt, but Arbitron rarely shows a woman wearing a meter. (Use Google Images, search for “Arbitron PPM meter” to see what I mean.)
Where do women wear the meter?
A likely possibility is that a woman puts the meter in her purse. It is certainly where most things go.
But what about the microphone? Can a PPM meter “hear” through a purse? The easiest way to find out is to put a purse over your head. Can you hear a radio playing? If you can’t make out the radio station wearing a purse over your head, there’s some question whether the meter can.
What about a man wearing the meter on his belt while wearing a heavy coat. Can a PPM meter “hear” through a heavy coat? Again, the easiest way to find out is to throw a coat over your head and see whether you can make out a radio station playing.
Further complicating matters is radio listening in a noisy environment, and its impact on the meter’s ability to reliably register a station’s code.
Ever listened to a radio station at a bar or noisy party, or drive down the road with the windows down?
We humans have a rather sophisticated auditory system. We can filter out noise and selectively focus our attention to hear a radio station even in a noisy environment. The meter has no human brain to distinguish between signal and noise.
Arbitron admits the meter has problems reliably detecting station codes in noisy environments, which is why it has developed a crediting process to fill in gaps at times when a meter detects fragments of encoded audio but can’t identify it.
The company addresses the problems as best it can, but missed codes are inevitable. It is impossible for the meter to get 100% of all codes 100% of the time, which means some radio listening goes uncredited.
It is inevitable.
Arbitron can’t control how the meter is carried. The company can encourage panelists to wear the meter on the outside of their clothing, but it has no way to know how people are actually carrying the meter.
Arbitron cannot control the environments in which radio is played, and we know people listen to radio in noisy environments.
So it really never knows whether the absence of apparent radio listening with PPM means people aren’t listening to radio, or that circumstances prevent the meter from detecting a complete code.
Instead of worrying about these things, Arbitron only monitors motion.
Motion is one thing that Arbitron can reliably measure and track, which is why the only requirement for a panelist is that the meter be in motion a total of eight hours a day (less for children).
So the woman with the meter in the purse is OK. The man wearing the meter on his belt under a suit jacket and heavy overcoat is OK. The student with the meter in his backpack is OK as long as each keeps the meter moving at least eight hours.
Each of those meters will be counted in the day’s in-tab.
In a previous Programming to Win column (6/21/13) I encouraged readers to use a fitness tracker to simulate the experience of wearing a PPM meter. It helps to better understand the challenges that PPM panelists face in wearing their meters throughout the day.
We can also simulate the challenge of making sure the meter reliably picks up station codes by using a smart phone voice recorder.
Many smart phones include a voice recorder using a microphone much like the PPM meter microphone. Play the radio station at a level where you clearly hear the station, set the smart phone to record, and then put the phone where you might wear the meter if you were a panelist.
You will probably find that the most convenient places to carry the PPM are the ones that hide the meter away.
These issues may be behind the curious phenomenon of identical listening spans for all formats. According to Arbitron, listeners to every format from News Talk to Rock listen ten minutes at a stretch. Not nine, not eleven, but an identical ten minutes.
While there’s no way of knowing without looking at PPM panelist level data (which Arbitron steadfastly refuses to release), perhaps the identical ten minute listening span reflects the meter’s ability to maintain a reliable data stream, rather than identical listening patterns across formats.
Next time you’re out with your staff take turns putting a purse over your head, or throwing a heavy coat over your head and try to listen to the radio station. You may learn something about the way listenership is measured. And you’ll certainly gain the attention of everyone around you.
Richard Harker is President of Harker Research, a company providing a wide range of research services to radio stations in North America and Europe. Twenty-years of research experience combined with Richard’s 15 years as a programmer and general manager helps Harker Research provide practical actionable solutions to ratings problems. Visit www.harkerresearch or contact Richard at (919) 954-8300
