Mac Black said:They're a diary market so they still believe in that 'quarter hour maintenence' nonsense.
All "quarter hour maintenance" means is observing the fact that it takes 5 minutes worth of credit in any quarter hour to get credit for that 15-minute period. The only difference is that the PPM accepts any 5 minutes, while in the diary they must be consecutive minutes.
Whether summed or consecutive, the "nonsense" about quarter-hour maintenance is one of the fundamental facts of Arbitron ratings.