Back when the Billboard Hot 100 chart first started, it combined record sales, radio airplay, AND jukebox picks to establish if/
where a song would fall on the Hot 100 list. Why do you think they used three items together (record sales/radio airplay/jukebox picks) rather than just one of the items?
At that time, record sales, radio airplay and jukebox pick where the 3 ways of media diffusion for musicians. People would normally listen to music according to one of these 3 platforms according to their lifestyle and economic position. It is also known that certain music genres could be associated to one or another platform. Therefore, limiting the quantification of reproductions to only one platform would create a bias that would produce a distortion in the information presented.
