Former Associate Publisher of Charts at Billboard Magazine, Michael Ellis, discusses how he changed the Hot 100 charts in 1991 from a system where retail stores called in their sales and radio stations reported their playlists to the historic transition to monitored real airplay and real sales through BDS and SoundScan.

We also discuss how today's charts are measured and why Michael believes the current system has flaws. Michael, who also served as Music Director of Z100 New York, reflects on the station's launch and how the music was selected.