Greg Harris, president and CEO of the Rock & Roll Hall of Fame, defended its history with heavy metal, saying the genre was “celebrated” and predicting that metal bands that haven't been voted in yet would be inducted in the future.

While definitions of heavy music vary, it can be argued that only two inducted bands – Black Sabbath in 2006 and Metallica in 2009 – are genuinely metal groups. Both Judas Priest and Iron Maiden have been nominated in recent years, but neither made its way through the process of being voted for by the 1,000 industry professionals who cast ballots every year.

“It’s an interesting one,” Harris told Audacy in a new interview, when asked about Maiden’s failure to be on the induction list this year. “We celebrate all forms of rock ’n’ roll. They were nominated – we nominated Maiden, Judas Priest have been nominated, we put Def Leppard in. ... Those that are nominated, over 80 percent of them eventually do get inducted. So it’s really a question of, let’s keep nominating them, let’s get ‘em on the ballot and let’s get it out to the voting body. This ballot had 16 artists on it … they just can’t all go in.”

Harris said the “common thread” among inducted artists was “impact and influence,” pointing out that New York Dolls – who also failed to be inducted this year – “didn’t sell that many records, but everybody that bought ‘em wanted to start bands.” He described rock as an “attitude” that’s “always pushing for change; it’s frequently a voice for the voiceless. … Rock ’n’ roll is a spirit, it’s an attitude.”

The class of 2021 includes Todd Rundgren, Tina Turner, Carole King, Foo Fighters, the Go-Go's and Jay-Z. The induction ceremony takes place on Oct. 30 in Cleveland and will be broadcast later on HBO.