During the late 80s and early 90s the industry underwent a transformation and restructured, catalyzed by three distinct factors. Record companies no longer viewed themselves as conduits for music, but as functions of the manipulations of Wall Street. Companies were acquired, conglomerated, bought and sold; public stock offerings ensued, shareholders met. At this very same time, new Nielsen monitoring systems -- BDS (Broadcast Data Systems) and SoundScan were employed to document record sales and radio airplay. Prior to 1991, the Billboard charts were done by manual research; radio stations and record stores across the country were polled to determine what was on their playlists and what the big sellers were. Thus, giving Oklahoma City, for example, an equivalent voice to Chicago's in terms of potential impact on the music scene. BDS keeps track of gross impressions through an encoded system that counts the number of plays or "spins" that a song receives. That number is, thereafter, multiplied by the number of potential listeners. SoundScan was put in place at retail centers to track sales by monitoring scanned barcodes of units crossing the counter. A formula was devised whereby the charts were based 20% on the SoundScan number and 80% on BDS results. The system had changed from one that measured popularity to one that was driven by population.
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