The very latest on
Portable People Meters

Arbitron's main man on how they do a better job  

By Kevin Downey

    It may seem strange for people to get excited about a little electronic device that measures broadcast media audiences. But media people did get excited when Arbitron began testing the Portable People Meter in Wilmington, Del., last year. It held the promise of correcting a slew of problems that media people saw in the way local broadcast media are measured. Specifically it could replace the paper diaries now used with a passive system that would measure radio, TV, and cable audiences continually and, for the first time, include ongoing measurement of usage outside the home. And the perceived importance of the PPM has only grown. It’s become clear to media researchers, for example, that the PPM could play a key role in the development of the multimedia optimizations that many of the biggest agencies are working on. But some of the excitement surrounding the PPM has given way to impatience as the pace of Arbitron’s methodical testing, although planned, seems painfully slow, with a rollout still more than a year away. Marshall Snyder is overseeing the development of Arbitron’s Portable People Meter. He spoke to Media Life yesterday about the system, its potential to replace outdated measurement systems, and when it might move from the testing stage into widespread use.



Can you explain how the Portable People Meter works? And why is it an improvement over the paper diaries now used to get demographic ratings for radio, broadcast TV, and cable?

    It works by imbedding an inaudible code in the audio portion of a transmission. That code identifies the source of the audio, whether it’s a television station, cable network, radio station, or perhaps a satellite distribution system.
    That code has been proven to survive all kinds of compression, decompression, digital distribution and all of the processes that might occur. It survives.
    There is a decoder, the PPM unit, which is a pager-sized device that people wear. They keep it on from the time they get up in the morning until they retire in the evening.
    That decoder device captures the code of any media that the individual is exposed to.
    At night, people put the PPM into a docking station that recharges the battery. And that’s when the data that is stored in the PPM is downloaded to a collection unit, which each night calls our central computer and delivers all the data from the people in that household.


What is happening now with the PPM test in Wilmington? How many people are participating and how many media outlets are involved?

    We invited 38 radio stations to participate and encode their signal. All 38 are doing so. We invited the eight television stations in Philadelphia to participate and all eight are doing so.
    We targeted 25 cable networks and, as of this moment, 21 are encoding their signals.
    There are no internet or satellite companies involved yet.
    The number of people involved is in the neighborhood of 240.
    We’re now in the last month of the Wilmington experiment, and this week we began the sampling for deploying the PPM panel in the Philadelphia market.
    That includes Wilmington. In that process, we will be replacing the panelists that have been part of the test with a fresh panel.
   The recruitment for that panel will begin in the first part of January. But we’re out there now doing what is called an enumeration survey, which provides the sample base for the original selection.
    We’re going to have 1,500 people installed in Philadelphia by the end of the first quarter. We intend to have 3,000 by the middle of the year. That latter number is flexible, depending on reactions we get from the marketplace.
    But we don’t intend to stop at 1,500 people. We expect that everyone interested will be encouraging us, so we’re making plans accordingly.


Will there be any changes made to the test when it expands throughout Philadelphia? Is it simply the same test in a larger geography with more people?

    We will continue to focus on cooperation rates and all quality indicators.
    We think we know fundamentally how to get a representative panel of people to be a part of this process. But we’re not finished refining those techniques.
    We’ve made some enhancements to the technology, which come in the form of additional capabilities.
    One of those capabilities will be a time-stamp included in the code, so that we will know the time of the broadcast. And the PPM will capture that code, along with its own time of exposure. Those two different time-stamps will let us determine if something has been time-shifted by TiVo or the traditional VCR.
    When we reach 1,500 people, we’ll be ready to show to the market outlet-level ratings. That is to say, they’ll be able to see individual stations and cable networks. The sample size up until now has not allowed for that level of scrutiny.
     We also have new batteries that have a longer life. The PPM uses up a lot of batteries because there’s a lot of processing going on. So we’re going to have a longer life for the PPM before it needs to be recharged.
    There’s also a redesigned docking station. The panelists will find it to be much more attractive and smaller. It will be a friendlier piece of equipment from an appearance point of view. The same is true of the collection unit, which is pretty small now.
    The coding unit is going through another iteration. The one we are currently using is performing just fine but it’s two-inches thick. The new one is one-inch thick and it has all the capability of the one currently in use, plus more sophisticated electronics in it.
    We’ll also provide an outlet monitoring system, which has been requested by television stations and cable networks. That system’s purpose is to send a message to people at the station that alerts them if the encoder, for some reason, is not sending out an encoded signal.
    We’re putting in more of the insurance or fail-safe processes that you need to have in order to have this type of service.


Will there be any changes to the data collected by the PPM during the next testing phase?

    We’re looking into measuring streaming media on the internet and satellite distribution services, in addition to the more traditional radio, television, and cable.
    A lot of the refinements have to do with what we ask of people and how we encourage them to do the job that we need done, meaning to take the PPM out of the dock, carry it with them, and put it back in the dock in the evening.
    And they need to keep the motion-detector, which is inside the device itself, satisfied that it is being carried. The indication that it’s satisfied is a green light on the side of it.
    If that light stops going solid-green, it begins to flash, which is an indication to people that they haven’t kept the PPM with them and in motion. But the PPM is always recording what it hears, in terms of codes.


How do you know the data from the PPM are better than those from the paper diary?

    Better is measured in a lot of ways. It can be based on face validity or validation experiments.
    Let’s deal with face validity.
    Those of us who have been dealing with diary measurement for a long time know that it’s difficult to get younger people to participate reliably over long periods of time. We’re seeing a difference in the media exposure among younger people in ways that are logical.
    As it relates to television, we have also observed a difference between men and women when you’re looking at diary-based demographic gathering. With the PPM, it’s more equal.
    So to the degree that these other systems are doing things well, they had some deficiencies that have been observed and accepted for years. That makes the PPM better.
    It also makes it better that you have the opportunity to observe a full set of media exposures, no matter where they occur.
    Also, because of the fact that it’s electronic, it captures what it captures and does it the same way each time it’s put in the same situation. It’s not subject to the human frailties of whether people remembered and later accurately made an entry about what media they were exposed to.
    There are a number of intrinsic facts in the data that bear that out.
    For example, with cable, I don’t think there’s anyone around that would argue that it’s been under-reported. So when you see that the average quarter-hour rating has changed in a meaningful way, that has face validity.
    There are a number of different ways to consider what’s better.
    I think the agencies will think it’s better that the demographics are measured continuously. I think the fact that the PPM has what no other research vehicle has, which is a built-in quality-assurance measurement system, will make them think it’s better. The diary certainly doesn’t have that, the set-meter doesn’t, and the set-meter People Meter doesn’t.
   But there’s a motion-detector in the PPM that tells us something about how well people are following our instructions. And if they don’t follow our instructions, then we won’t tabulate their data that day.
   The fact that there is quality assurance built in makes it better.

November 1, 2001 © 2001 Media Life

-Kevin Downey is a staff writer for Media Life.

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