Derm has some of the highest self selection prior to applicants applying
Derm had the highest AOA percentage of any specialty by far (47% vs 43% vs <40% everything else)
Derm had the second highest step 1 score of any specialty (Plastic surgery had 1 point higher this year)
Derm has one of the highest research outputs of any specialty (19 this year)
Derm likely has the highest percentage of research years (can't prove this for sure, but I don't see any other field that does research years with this consistency)
Derm has a significant prestige bias that pushes out a lot of people from lower tiers schools
There are many people with 0 interviews that don't show up in the data
The merger added roughly 50 more spots to the match denominator this year
Also there happened to be a small contraction in US seniors applying in 2020. Higher or same overall quality, but I think 50 or so less than 2019.
Comparing the raw match % between specialties means nothing.
So no Derm is not the "8th most competitive specialty". I would say its a very close tie between Derm = Plastics = Neurosurg = ENT = Ortho = IR for most competitive specialties. Trying to compare within these fields is stupid and pointless, and honestly who cares.