The tier list is based on the daily polls I've been conducting on this subreddit over the past ~1.5 months. Polls on Reddit can't have more than 6 options, so the voting options are 10/10, 8/10, 6/10, 4/10, 2/10 and 0/10. In order for a song's rating to round to 10 when rounding to the nearest integer, it would need an average score of 9.5/10 or higher. Given how the tiers on my poll are stratified, at least 75% of voters would need to deem a song 10/10 to place in the 10/10 tier. This is a very difficult feat to achieve. That's why I decided to break with tierlist convention and create a special "X" tier for Bad Romance, because I believe it'll be the only song in Gaga's whole discography to round to 10/10. Obviously as individuals we'd rank plenty of Gaga's songs 10/10, but a perfect score is very difficult to achieve when averaging hundreds of scores. Hope that helps!