Back before Nielsen introduced SoundScan in March 1991, the Billboard album chart was compiled by having retail assistants fill out paper forms by hand listing the store’s best sellers. Some 26 years later, the digital age has ushered in a time of quantifiable, instant data with which a music company can track even the most granular of metrics in the blink of an eye — or a click of the mouse, as it were.

So why, then, are there discrepancies between the Nielsen Music chart, which powers, among other tallies, the Billboard 200, and BuzzAngle Music’s consumption chart, a more recent entry to the chart game which differentiates itself as “an analytics company.” 

One such inconsistency occurred just last week when Nielsen had the stream-heavy DJ Khaled album, “Grateful” (released by Epic Records on June 30), at No. 1, while BuzzAngle placed Imagine Dragons’ physical/download-supported “Evolve” (Geffen) atop their album chart, amid industry whispers about the former benefiting from 20 million phantom streams, according to a source.