I want to put in a comment about the ratings. How were ratings done? Now ratings are divided into different groups. For instance between the age groups between men and women. The overall ratings posted on Arbitron are listeners 12 and older. The ratings are ranked with all these groups mixed in together. Just check out the ratings @ arbitron.com.
Thanks for the comment. When I started in radio in the late 50s while I was still in high school, there were several rating services. C.E. Hooper had Hooperatings. They were telephone surveys. The sample size was usually around 1000. They were fast and you could get the results back quickly. Several stations could pay or just one. You only got legal copies if you subscribed. It was often rumored that subscribers usually got better ratings. I have no first hand experience with that. I felt Hooper offered a reasonable service. There was not much demographic data and I don;t believe they called after 9 PM, Programmers liked Hooper because you could get the results quickly. Sales didn't care too much for Hooper unless you had a strong number one.
There were several other smaller rating services whose name escapes me.
Pulse started becoming the most popular rating service in the 60s. They offered
larger sample sizes, more demographics, county by county counts, but slower service.
It took several months from the end of the survey to the arrival of the book.
Pulse used the diary method. I have a problem with that mythology because it requires the person to remember to write down the stations they were listening to and the time. You could break out a DJ show in 15 minute increments. Pat Walsh, long time KAAY manager was a big ratings fan. He subscribed to Pulse books from markets all over the country along with all the counties in Arkansas.
I have no experience with Arbitron and cannot comment on it.
Little Rock University did car radio surveys for several years. They had students at high traffic locations who would interview people stopped at a light. The had a great sample size and good demographic info.