For the purposes of this project, "popular music" is an all-encompassing term that includes rock, hip-hop, dance, country, folk, and experimental noise music, plus a bunch of other things too. My review database includes some jazz and classical music reviews as well. It's common for popular music magazines to include music that "crosses over" to many different genres; pop reviews are usually written with a certain age demographic in mind rather than a certain genre, and the average music listener touches upon a number of different genres in the search for the perfect life soundtrack.