Encoders are free to all stations that are home to a market, they require minimum effort to install and have no downside.
the downside is if you are a WJIB and ASCAP/BMI uses the data to increase your music licensing fees through the roof.
If you are a station that sells itself by saying they have X amount of potential listeners, and no desire to sell itself to a single P1, something a WUNR or other leased time or brokered arrangement does by making the purchaser attract their audience, ratings mean nothing.
The Arbitron/Nielsen folks know the population of a given market and can probably estimate with reasonable certainty the percentage of the population that listen to the radio and for how long and how many times a week without every station in the market encoding.
It is only a matter of time before Boston falls out of the top 10 markets due to the population shifting south and southwest, If it wasn't for them expanding the DMA Boston would have fallen out of the top 10 long ago in my uninformed opinion.
After LA, people are giving ratings data a whole new look... a couple of households were able to corrupt the data for a market much larger than Boston... what does that say about sample size and R factors?
Anyone remember Providence a few years ago and the wife of a local host getting a bunch of diaries?
Hell I have filled them out.. when I was not working in the business.... I was not totally honest, but then again I have been elected to public office more than once ......
There are lies, damn lies, and statistics someone once said. The sales weasels are going to take any data and twist it to their own purposes.... and if that wasn't the case there would only be 6+ data, not data created to prove that blind,deaf transvestites with one arm ,3 legs, hispanic surnames and are vegetarians are most likely to listen to Suzie Creamcheese in the morning on WTF radio 96.4 than any other station