Add Value to Your Radio PSAs via Electronic Monitoring

Requires Strict Creative Parameters

By Bill Goodwill


While radio offers PSA planners many advantages, such as cheaper production cost and the ability to target specific audiences, it also has some weaknesses, and one of them is getting accurate evaluation data.

The primary way radio PSA exposure has been evaluated is by bounce-back cards, which have some significant limitations. 

First, only about 20% of stations return them, and we know from sending reminder postcards that many stations use PSAs, but do not report that usage.  We try to make it very easy to use the BRCs (business reply cards) by putting simple information stations can circle to indicate frequency and duration of usage.  We also provide free return postage, but still many stations do not take the time to return them, meaning the client gets no credit for usage.

A few years back a company called MediaGuide developed the first electronic tracking of radio PSAs, and we were among the first distributors to use that service to provide a more accurate way to measureradio PSA usage.  Unfortunately, they went out of business, leaving us the bounce-back card method of radio evaluation once again.

Now the A.C. Nielsen Company – the same firm which provides accurate broadcast TV monitoring – has developed technology to monitor radio PSA exposure.  The service, also called SIGMA,  offers  radio tracking in 140 markets, covering over 2000 radio stations across the U.S. and Canada, including satellite and national networks. 

"Fingerprint" Technology

Nielsen SIGMA radio detections are collected using what is called “pattern recognition technology,” which works very similar to fingerprint detections.  Generically, it called “passive monitoring,” because there is no need to place a code on the radio master.  We simply send the audio files to Nielsen and they create the patterns to track each creative.

However, there are some creative requirements to consider that could greatly affect results, which include:

  • Audio must be unique in order to be reported individually. For example, if a 30 second PSA is cut down to 15 seconds, Nielsen cannot identify and report them individually unless there is enough difference between the audio tracks. There must be a different voice or background on each creative. A new or different phone number is not considered unique.

  • The entire spot is encoded in 6-second segments.  If it is a 30 second spot, which has 5 segments and 3 of the 5 match, while 2 do not, the 3 are generally going to match as a duplicate for the first pattern already in the system.  Nielsen also allows us to submit the audio to be monitored, and their system will tell us if there is enough of a difference for unique reporting.

Audio File Requirements

The following are the minimum requirements for audio files to be tracked.  If your file does not meet these requirements, the release will be rejected.

  • MPEG 1.0 layer 3
  • Stereo (mpeg file must be created with one of the following bit values: 00 - stereo, 01 - joint stereo, or 10 - dual channel stereo)
  • Minimum 128kbit (may be higher but not necessary) and 44100Hz or 44.1KhZ
  • Files cannot include headers
  • Minimum of 15 second spot needed
  • Clients can use Audacity software to convert the MP3 to stereo or make minor changes.

For a more definitive article on how to plan and implement your radio PSA campaign, go to: