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Using a Logic Tree to better understand coinage defects

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There’s a little tool called a “logic tree” that can help collectors better understand where a defect occurred in the coinage process, and how it might have happened. Here’s a basic version. Take, for example, the surface defect known as “orange peel,” that is under discussion on the PCGS board.


Step 1 – the Roots

Describe the defect in as much detail as possible. For example, is it confined to the fields, or extend to the devices and lettering? Is it uniform or irregular is distribution? Does it affect only one side of the coin? Is there a pattern to the defect? Do any two coins share identical (not just similar) defects. Is the defect specific to a design, production type or metal alloy? Is the defect specific to a date range or to certain mints?


Step 2 – the Trunk & Limbs

Organize the Step 1 information in a table that cross matches characteristics. The trunk might be a production method (proofs only, etc.); large limbs might be specific mints, or alloys.


Step 3 – the Branches

Trim off all the limbs that lead nowhere, such as those for certain mints or alloys. Examine the remaining branches for patterns: are there observations that exclude processes? For example, if two or more coins share identical defects, then the defect cannot be caused by planchet production – look elsewhere in the coining process.


At this point you have dug down to the roots, climbed the trunk and big limbs, and are now out on a branch looking at the leaves (or maybe there’s an angry robin looking at you). Use the cause-and-effect process of elimination to focus on the mechanically and physically plausible location and coinage process step.


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I think in terms of flow charts for trying to clarify classification; not just for defects but for general judgments on coins. The first judgment would be whether a given coin is genuine or not; next you would focus on surface issues; then possible die varieties; finally if the coin is not impaired, what would a likely grade range be. Clearly the experts and sharpest graders out there can narrow down all the important aspects related to the quality of coins rapidly and the more they look at the better they get; most of the rest of us are not sharpening our senses by reviewing numbers of coins and all the varieties in a thorough manner so it becomes tough to make those judgments when called on to do so.


It is interesting to see topics like this, sir, and would be interested to know what process graders use to make proper and accurate judgments on coins.

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The key point to the OP is that no assumptions can be made until all factual conditions have been assessed.


Flow charts work better for processes rather than logic.

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