"agencies go through training on how to buy w/ PPM and aside from "Christmas Music" and Format changes they are trained to use 3 monthly surveys .... any sales rep that encourages their clients to do anything less aside from Christmas and format changes is doing their client a dis-service"
Actually they go through about three hours of Arbitron PPM "training" and then go back to the way they have always done business. Agencies are ultimately "trained" to manipulate the books and data in the way that best serves their pricing needs. They will buy monthly, qurarterly, two-book, three-book, whatever it takes to get the stations in the worst possible position of negotiation. It is why beer and soda business is always bought on fall books when the schedules air in the summertime. Younger demographic listening is lower in the fall, so agencies use the lower ratings to hammer stations on summer business. Sales reps rarely "encourage" clients to do anything. With few exceptions, the clients get what they want from weak kneed reps who have no management support and are instructed by their bosses to "get the business no matter what it takes." You can bet agencies will default to the worst recent "month" when looking to negotiate with a station. PPM is not good for radio sellers.