It seems to me like after AT40 went away from the Hot 100 in 1991, even though both AT40 and Casey's Top 40 used radio charts, Casey's Top 40 was a closer match to the Hot 100. For example, Smells Like Teen Spirit, a Top 10 Hot 100 hit, also reached the Top 10 on Casey's Top 40 but never aired on American Top 40. Another Top 10 hit, Achy Breaky Heart, had a multi-week run on Casey's Top 40, but couldn't rise above #38 on AT40. Did the two shows use different radio markets in compliling their charts? I'm just wondering how two shows using radio as their basis could have a Top 10 hit on one not even appear on the other.
In 1992 I don't think R&R was using a 100% accurate data gathering approach or was a different method until sometime in March/April 94. That's why "The Sign" climbed back to #1 after I believe 2 weeks out and other songs were in very different positions than the week before.
Post by Shadoe Fan on Nov 13, 2012 16:08:27 GMT -5
In 1992, AT40 was using the Hot 100 Airplay (formerly known as Top 40 Radio Monitor) chart. That chart used the BDS computer technology that is used today, but the list of stations monitored was much smaller than today and focused on Top 40 stations.
The Hot 100 Airplay chart uses "audience impressions" to rank the songs. It calculates the number of people that hear the song each week. Therefore songs that are played more in large markets such as Los Angeles would get higher rankings than songs played in smaller markets.
The Radio and Records chart in 1992 still used the old way of calculating airplay. Stations would send in a list of the their most played songs, and these were compiled to create the airplay chart. Equal weight was given to all radio stations, I believe. Radio stations often dropped off songs off their list even though they were still playing them.
Thus many songs that were played more in large markets were only heard (or charted higher) on AT40 than CT40, and the opposite was also true. In addition, songs stayed on the chart a lot longer on the Billboard chart due to the methodology, and that kept songs off the Billboard chart that made it on the Radio and Records chart.
I know that CT40 certainly reflected more of what I heard where I lived, since I listened in smaller markets.