Let's say I have two lists of items. In both lists, I am interested in a subset of the items according to some property. If one list includes almost exclusively items that have that property, then a common way of describing the situation in engineering lingo is "high signal to noise ratio". The other list only contains a few items that contain the desirable property, and is otherwise filled with items that I'd like to filter out. It has a low signal to noise ratio.
What is the proper term to describe the quality of those 2 lists?