Back in the late 70s clocks began to evolve into a pattern that was supposed to extend TSL. A very skilled programmer of the day (Buzz Bennet I'm pretty sure) studied the whole Arbitron system of recording the listening and determined that because of the organization of the diary pages and the way they granted you a quarter hour by rounding up the listening that if you waited till :17 or :20 and that was properly recorded in the diary you would get credit for 2 quarter hours. Ever since in most hours outside of morning drive we typically sweep music from :55 all the way to :17 or :20. We also take the next break (if we have 3) around :37 to insure we get a full quarter hour in the 3rd segment of the hour and the last break is usually closer to :52 or :53 ideally to cover the last segment.
While the rule is right as you look at the diary layout and the rules for crediting that grants you a full 1/4 hour after 7 minutes 2 realities stand out:
- Not everyone is walking around with an atomic clock in front of them while entering the data. Do they really know the 'exact time' when they scribble it down?
- Most diaries are not filled out while actually listening - but are often filled out at the end of the day or maybe on Thursday morning for the whole week.
But, we sort of pushed those realities aside and nearly everyone adapted the formula. It probably did work to a certain extent as nearly everyone still breaks pretty close to this formula and we all may have extended TSL as you punched away you often find commercials on many stations in unison. The listeners probably think it's a govt. plot.With PPM we have real data coming in and it's all controlled by an internal clock that's probably pretty accurate. When Arbitron breaks out he PPM data the listening is nearly equal in each of the quarter hours. From :53-:08 26% - :08-:23 24% - :23-38 25% and :38-:53 25%.
Did we gain anything from all these years of setting the clocks on the Buzz standard? I bet not. I bet some brave programmer will start breaking around :10 and be able to sweep either :20 or :55 and be the only station on the planet playing music there. Don't know that anyone in a PPM market has tried - but it could happen.