Distribution of ranks, state census and provenance
By Kyle Knapp for PCGS ……
Any introduction to coin grading begins with general and theoretical descriptions of each grade category: mostly full rims for “Good”, usually full letters for “Fine”, and so on.
However, as one gains experience or begins to specialize, more problem-specific lenses are needed for a meaningful interpretation of the numerical rating assigned to a particular piece.
Three of the most important of these are rank distribution, state census, and provenance. Although it is not always necessary to determine a coin’s grade on the Sheldon grading scale, the associated grade distribution, condition census, and provenance data allow collectors to make more informed decisions. informed, assisting experts with authentication and classification, and adding an exciting historical element to important pieces.
The distribution of scores for any issue describes the shape of the certified population relative to the Sheldon scale. For rooms with a significant population, this distribution will be largely normal (i.e. following a bell-shaped curve). Knowledge of a coin’s rank distribution invites consideration of a coin in the relevant survival and availability context and can add tangible meaning to an otherwise ethereal numerical rating.
To take a common example, the Morgan Dollars 1880-S have a roughly normal distribution with an average numerical rating somewhere around MS64. Morgan dollars of this date were produced in abundance, with many never leaving bank and government coffers. But they were also made and handled by methods consistent with the production of circulating coins and so often suffered sack marks and other minor surface abrasions typical of such life. Distributions for coins produced for numismatic purposes – proofs or commemorative coins, for example – often center on much higher qualities, while those for rarer coins whose entire issue has entered circulation would have much lower peaks on the Sheldon scale.
While the ratings distribution takes into account all certified examples of a particular problem, the state census zooms in on the right tail of the distribution, listing and ranking the most well-known parts in order of condition. For rare problems, this list may include the entire population: the five 1885 trade dollars are well known, for example. Evaluators use the state census both as an authentication tool and as a grading guideline. When a newly encountered piece is submitted, it may be compared to the best existing pieces for signs of inconsistency or deficiency and graded appropriately.
State census data are abundant for some series; big penny collectors appreciate the glossy leather-bound books containing photographic censuses of the condition of each Sheldon variety, while 1794 Dollars and 1802 half-dimes have stand-alone reference volumes entirely dedicated to this purpose. However, for many series, this information remains to be sorted in depth – significant and rewarding work for a student of numismatics.
Finally, provenance attaches a dating history to individual pieces in the state census, identifying public appearances and changes in ownership throughout their lifetime. Each time a coin changes hands at auction or appears as part of a major collection, a new stamp is added to its “provenance blockchain”, adding a unique story and romance to this example. .
Many parts can be traced directly back to the US currencylike the proofs purchased at the Philadelphia Mint counter by collectors such as george clapp and Walter Childs early 20th century, while others date back to the first generation of American numismatic auctions in the mid-19th century. A well-documented provenance can help deter fraud and help recover stolen items. PCGS uses verifiable provenance, usually in the form of new, unopened boxes, to ensure that newly released coins are eligible for “first minting” and other special designations.
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