Pharrell Williams is perhaps the clearest example of how narrow our measure can be. As a producer and member of The Neptunes and N.E.R.D., he helped shape two decades of pop and hip-hop, and as a guest he sang two of the biggest songs of 2013, "Get Lucky" and "Blurred Lines". By any sane reckoning he is the opposite of a one-hit wonder.
But our method counts only songs credited to him as a lead artist, and there one record towers over everything. "Happy", from the Despicable Me 2 soundtrack, became a global, inescapable number one and now sits near 1.7 billion plays.
His other lead singles trail far behind, with "Freedom" and others well under 250 million streams. Dividing "Happy" by his second biggest gives a ratio of about 7, past our 5.0 line.
So by our strict, numbers-only measure, and counting only his solo lead releases, Pharrell Williams registers as a certified one-hit wonder. It is an almost comic illustration of the method's blind spot: one of the most influential music-makers alive, defined on his own streams by a single feel-good anthem.