That study, and accompanying chart, strike me as a little dubious, since the author is vague about the methods used. In the first article in the series, the author says:
I’ve undertaken the first population study of performing pop musicians (n=12,665) from all popular genres who died between 1950 and June 2014 of whom 90.6% (11,478 musicians) were male.
How did the author sample the category of performing pop musicians who died between 1950 and 2014? Only 12,665 people fall into that category? A quick Wikipedia check of the membership of the American Federation of Musicians of the United States and Canada shows that their membership in 2016 was 75,542. Using that as a rough count of musicians, and assuming an approximate 1% death rate, one would expect about four times that number for a 64 year period. And that’s just the US and Canada.
The author says:
Data on age, circumstances and manner of death were accessed from over 200 sources, including The Dead Rock Stars’ Club; Nick Tavelski’s (2010) Knocking on Heaven’s Door: Rock Obituaries, Pop star mortality; R.I.P. Encyclopaedia Metallicum; Voices from the Dark Side for Dead Metal Musicians; Wikipedia’s List of Dead Hip Hop Artists and Hip Hop obituaries;
I went to rapper death websites, Dead Punk Stars and similar sites for all popular music genres. The genres I covered included African, ballad, bluegrass, blues, Cajun, calypso, Christian pop, conjunto, country, doo-wop, electroclash, folk, funk, Gospel, hard rock, hip hop, honky tonk, indie, jazz, Latin, metal, new wave, polka, pop, psychedelic, punk, punk-electronic, rock rap, reggae, rhythm and blues, rock ‘n’ roll, rockabilly, ska, soul, swamp, swing, techno, western and world music.
That is a large number of sources. But several of them specialize in noting scandalous deaths, and so if they miss people, they will miss people whose deaths were boring. Do those sources taken together really count all popular musicians who died in that period? Or only famous headliners, noteworthy enough to earn a listing, and who might be expected to live a more intense, high pressure lifestyle than a low-key career session musician who simply died in bed?
Also, as the author notes at the very end of the article, rap and hip hop have not been around very long. So, the class of rap and hip-hop artists who have already died prior to 2014 is by no means a representative sample of all hip-hop artists. Instead, that sample consists of people have something in common: they died relatively young. Thus, what that middle column shows is that about half of hip hop artists who died young, and were well enough known to appear in the sources she used, died by homicide.