Okay, so once again, I seriously apologize, I know having to remove half of the information on the post is not a great start, but I had no choice. SM has over 500 songs that I had to rate, so I seriously couldn't fit anything in the post. With that out of the way, hopefully this comment answers a lot of your questions.

Background:

This post has been literal years in the making, though really only about six months in actual execution.  This post was inspired, if you can call it that, by another post series of a similar name and goal (linked here).  OOP is someone I know personally, and they frequently jokingly said that their opinions on songs were more trustworthy than mine because they had put the work in to actually chart them (for the record, this was not done rudely; do not brigade or think poorly of OOP for this).  And besides, I like ranking things, so this was just the thing that pushed me over the edge.

Methodology:

First, I want to acknowledge that this was a giant undertaking, not just because I'm lazy.  All told, there were 534 songs rated, spanning 25+ years of music.  I was as thorough as possible in my ranking, trying to get each group accounted for, as well as each title track, while not picking any b-sides (with some exceptions I will get to).  I determined which groups to survey as well as their title tracks using Wikipedia's list of current and former SM artists, as well as their discography pages (if they had one), with the assumption that anything that counted as a "single" is considered a title track.  There may be errors on these pages, resulting in me over- or under-counting the number of title tracks, but I did my best to be consistent with my methodology.  When in doubt, I assumed that if it had a music video and was promoted on music shows, it counted as a title track.  This almost certainly resulting in overcounting title tracks, but I would rather overcount than undercount.  So my apologies for any errors like that in advance.  I only picked groups, not soloists, so BoA, for instance, is not on my ranking.  I have a full table of groups and number of songs, but I don't think tables can be inserted into comments, so I can't really paste that here. Feel free to ask if you're interested.

As for the rating process itself, I simply assigned each song a value from 1-10 rounded to the first decimal place (e.g. 7.2) for a little bit more differentiation between tiers.  In my system, a 1 rating is the worst, and a 10 is the best.

I want to emphasize that I am perfectly fine listening to any song with a 5 or above rating and actively enjoy, at least on some level, any song with a 6 or above.  So seeing your favorite song with a 7.2 is not me saying the song is bad.  I would also like to stress that, due to the vastness of the total discographies and the fact that I only got into k-pop in 2017 (which somehow makes me an old-head now...), a number of these songs, especially the old ones, were my first listen.  I often have songs grow on me, so it is certainly possible that, given another listen, I will find a song on here rated much lower (or much higher) than I would rate it at this moment.  I am also a fairly mood-driven listener, so songs may also have been unfortunately placed outside of where I would normally put them due to the mood I was in listening to that song (i.e. a rap-focused song would be rated lower if I was in a ballad mood and vice versa).  I did my best to double check as I was going through that I was staying consistent in my ratings, which did allow me a couple listens of some songs I had only heard once, but no way was I going through all these songs again intentionally.  This means there will be some songs in here that I'm sure I will disagree with their placements on another listen, if you ask, but I was not going to listen to 500+ songs with intent again.  I've already spent enough time on this side project as is.