• by Erik Sass  @eriksass1, July 17, 2015

After a year of rumor and speculation, Nielsen is preparing to address the controversy that erupted in recent months surrounding the impact of a new device, called Voltair, on radio ratings produced by its Portable People Meter technology.

The ratings giant will first discuss its stance on Voltair and PPM with clients in a conference call and Webinar on July 21, 2015,  followed by a public statement afterwards. No matter what happens, however, there are likely to be more questions generated by this hot-button issue.

Developed and manufactured by the Telos Alliance, Voltair works by boosting the encoded signal in radio programming that serves as an inaudible “watermark,” allowing PPM to detect the signal when the panelist carrying the device is nearby, thus giving the station credit for the audio exposure.

Beginning last summer, radio industry watchers began to observe an unusual phenomenon. After years of mostly even ratings or gradual changes, audience ratings for individual radio stations were suddenly spiking by 30% or more in a month after they began to use Voltair. These increases were especially noteworthy because they occurred in the absence of format changes or the introduction of popular new songs or artists.

This revelation has raised a whole slew of awkward issues. The most obvious question is whether the PPM can actually detect all the encoded signals included in various types of programming.

In order to keep the digital watermark inaudible, Arbitron, which developed PPM before being acquired by Nielsen in 2013, lowered the energy of the encoded signal to a level that PPM could supposedly still pick up without interrupting the listening experience. However, some types of programming -- most notably talk radio -- do not always produce enough energy in this range to mask the signal effectively due to frequent pauses, causing the system to lower the signal or stop encoding altogether.

Arbitron compensated for this with statistical calculations bridging the gaps in measurement in order to give stations credit even when encoding wasn’t active.

It now appears that the measurement gaps are more substantial than previously believed, resulting in large apparent dropoffs in ratings for these formats. This is potentially a serious issue; after PPM was introduced in 2007-2008, much of the conventional wisdom about radio listening (based on Arbitron’s previous paper diary measurement system) was turned on its head, with formats like talk radio suffering major drops in ratings. Radio programmers adjusted their strategies accordingly, in many cases laying off on-air talent or opting for non-talk formats.

Now, however, stations equipped with Voltair show substantially higher ratings for talk formats, as well as spoken word interludes in other types of programming, for example when radio DJs banter, than PPM previously indicated. Meanwhile, other formats have also experienced increases with Voltair. Nor is this a minor aberration: The nation’s largest radio broadcaster, iHeartMedia (formerly Clear Channel), is reportedly buying hundreds of Voltair units and installing them at stations across the country as it seeks to gain an edge in the ratings game.

Of course, all this could in turn affect advertising sales negotiations.

As of mid-July, media buyers asked about Voltair’s impact on ratings said they still didn’t have enough information to make a judgment, suggesting that it has so far had little impact on sales for individual stations or the medium as a whole. But uncertainty among buyers about the reliability of PPM ratings could conceivably erode trust in the radio environment.

By the same token, there is a potential upside, according to Richard Harker of Harker Research, a radio analyst and consultant who’s been following Voltair since last summer: if Voltair reveals that radio audiences are actually larger than previously suspected across the board, the entire industry could benefit from the boost to total advertising spending.

At the time of writing, the Media Rating Council -- which granted certification to PPM after a lengthy review process -- had not responded to a request for comment on Voltair. It may be worth noting that last month, Canada’s official media measurement organization Numeris banned the use of Voltair devices by Canadian radio stations.

So far, Nielsen has had no official comment on Voltair either, beyond one previous statement in April that it had not endorsed the device. The Webinar on July 21 will bring its first official statement on the subject. In the radio industry, at least, you know what everyone will be listening to on Tuesday.