>>33891226Tiers are based on usage. If a Pokemon doesnt reach like 3.45% usage or something in a tier, it gets knocked down and so on until its above that percentage or is banned from the tier.. The ban list are Ubers (OU) BL (UU) BL2 (RU) BL3 (NU) and BL4 (PU)
It used to account for all ELOs which is why we had mememons like Electivire in Gen 4 OU and Ambipom in Gen 5 RU but now it only counts usage above a certain ELO, to prevent shitters from fucking up the tier lists.
Usually a Pokemon is used because it good in the meta. Ubers is the only banlist thats played as a tier because of the sheer amount of Pokemon in the tier. There are also viability rankings in the forms that show off a Pokemon's viability. They are typically ranked S-D (and very rarely E)
S ranks are pretty much the best pokemon whether they are the best offensive, defensive, utility or splashability. They have very miniscule or zero flaws.
A ranks are very solid mons that are very good, but typically have a flaw that prevents them from being S tier
B tiers are pretty good mons that offer good synergy with above but have pretty big flaws in themselves.
C tiers are Pokemon that hold a specific niche that make them worth using
D tiers are Pokemon that are unviable in the tier but are only there due to proxy.
