Silver Dollars & Trade Dollars of the United States - A Complete Encyclopedia

Chapter 2: Value and Rarity Ratings
1 2 3 4 5 6 7 8

The Universal Rarity Scale

I propose the Universal Rarity Scale-one that is mathematically sound in its progression and relationship among its divisions, and one that will be applicable to any series. Stated simply, it is a geometric progression of numbers, rounded off for convenience in use, with each category containing about twice as many members as the 'preceding category. The proposed Universal Rarity Scale uses a simple geometric progression of numbers, as 1, 2, 4, 8, 16, 32, etc. (see the rightmost of each number pair):

PROPOSED SCALE DRAFT:
Universal Rarity Scale-1 = 1 known, unique
URS-2 = 2 known
URS-3 = 3 or4
URS-4 = 5 to 8
URS-5 = 9 to 16
URS-6 = 17 to 32
URS-7 = 33 to 64
URS-8 = 65 to 128
URS-9 = 129 to 256
URS-10 = 257 to 512
URS-ll = 513 to 1,024
URS-12 = 1,025 to 2,048
URS-13 = 2,049 to 4,096
URS-14 = 4,097 to 8,192
URS-15 = 8,193 to 16,384
URS-16 = 16,385 to 32,768
URS-17 = 32,769 to 65,536
URS-15 = 65,537 to 131,072
URS-19 = 131,073 to 262,144
URS-20 = 262,145 to 524,288
URS-21 = 524,289 to 1,048,576
URS-22 = 1,048,577 to 2,097,152
URS-23 = 2,097,153 to 4,194,304
URS-24 = 4,194,305 to 8,388,608
URS-25> = same progression

The suggestion was made to me by John Croon, and seconded by J. Alan Bricker, that the Universal Rarity Scale could be simplified by rounding off the numbers in higher categories. For example, URS-16 could be 16,000 to 31,999; URS-17 could be 32,000 to 64,999, etc. While this takes the DRS away from precise mathematics, it makes it easier to use. Thus, I give the final form of the URS as follows:

THE UNIVERSAL RARITY SCALE Universal Rarity Scale-O = None known
URS-l = I known, unique
URS-2 = 2 known
URS-3 =3 or4
URS-4= 5 to 8
URS-5 = 9 to 16
URS-6 = 17 to 32
URS-7 = 33 to 64
URS-8 = 65 to 124
URS-9 = 125 to 249
URS-10 = 250 to 499
URS-11 = 500 to 999
URS-12 = 1,000 to 1,999
URS-13 == 2,000 to 3,999
URS-14 =4,000 to 7,999
URS-15== 8,000 to 15,999
URS-16 = 16,000 to 31,999
URS-17= 32,000 to 64,999
URS-18 = 65,000 to 124,999
URS-19 = 1,25,000 to 249,999
URS-20 = 250,000 to 499,999
URS-21 = 500,000 to 999,999
URS-22 = 1,000,000 to 1,999,999
URS-23 = 2,000,000 to 3,999,999
URS-24 = 4,000,000 to 7,999,999
URS-25 = 8,000,000 to 15,999,999
URS-26>= same progression

Application of the Universal Rarity Scale

For the numismatist, the Universal Rarity Scale permits accuracy not hitherto known, For example, an 1884 trade dollar (10 known) is URS-5, while an 1885 (5 known) is URS-4. The 1870-S $3 and 1873- CC No Arrows dime, each of which is unique, are each URS-1 The 1873-S Liberty Seated dollar, of which none is known to exist, is URS-O.

Chapter 2: Value and Rarity Ratings
1 2 3 4 5 6 7 8

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