The format of a tier list cannot adequately explain when certain dolls should be used over others.
It is vital to read the explanations for a doll's placement, as in certain situations, a doll may be more or less viable.
Failing to do so can result in completely misinterpreting this tier list.
Tier 1 is composed of the strongest units in their class. These units will outperform their counterparts nearly all of the time in the current meta and there is no statistical reason to use other units over them.
Tier 2 is a wide-spanning tier. Included units range from good to mediocre but usable. The reason for their placement here may be that they are either not strong enough -- they are outclassed by a tier 1 unit -- or they are forced into a more specific usage area that impacts their overall versatility.
Tier 3 is composed of the worst units in their class. These units are simply not good enough to be considered mediocre and do not generally warrant investment.
Niche units are those that possess unorthodox uses and are not strong or viable outside of their very peculiar role. These units will be outclassed by most other units nearly all the time.