I'm always interested in the PPM rating results for our local radio stations. Often, when I learn the numbers, I'll even write about it. I just assumed PPM (Portable People Meter) dependably measured stations encountered, but apparently it has "blind spots".
This article was enlightening for this radio fan. Depending on the station's encoding, the PPM may or may not pick it up. In fact, if the station is primarily talk, it's often missed.
Voltair is a new service marketed to radio stations that promises "advanced audio signal processing to enhance the detectability of the watermark codes within the context of your programming objectives." In other words, it eliminates the blind spot so the PPM gives full credit.
In a couple of tests by Harker Research, ratings increased up to 61% when Voltair was installed. Nothing else was changed, and ratings spiked.
The most important lesson here is that the rumors about Voltair helping improve ratings are true. This is the clearest evidence that PPM as implemented is flawed.
PPM does not capture all listening, so it under-estimates radio listening–potentially by a lot for some formats.
The solution is for Nielsen to admit that the problem exists and agree to a time-table to fix it.
It is likely that PPM will never be perfect. It will never capture all listening, but missing 20%, 50%, or more should be unacceptable.
Remember, we don't know which stations are using Voltair and which are not. That makes an already imperfect system even more suspect. There has to be a better way to measure radio listeners.