Definitions for "Rarity scale"
Keywords:  sheldon, urs, specimens, bowers, alan
A convention for designating the rarity of a coin, such as Sheldon's system (with values such as R1 for common pieces and R6 for extremely rare specimens) and the Universal Rarity Scale invented by Alan Herbert (with designations such as URS3)
A system for designating the relative number of specimens known to exist. The two most commonly used in numismatics are Sheldon's scale (ranging from R1 for common pieces to R8 for those that are unique or nearly so) and the Universal Rarity Scale developed by Q. David Bowers (with the lower designations, such as URS1, indicating greater rarity and higher numbers for more common items).
an educated guess or estimate of the surviving specimens of any given coin or variety