Is A Lincoln Cent Doubled Die Submission To A TPG Service Likely To Pass Muster?

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PlutonianFire Valued Member United States 59 Posts	Posted 05/19/2025 04:19 am AN EMPIRICAL APPROACH TO BALLPARKING THE PROBABILITY THAT A Lincoln Cent DOUBLED DIE VARIETY PRESUMPTIVELY ATTRIBUTED BY A COLLECTOR WILL PASS MUSTER AT PCGS OR NGC For many reasons numismatic hobbyists submit their variety coins to a coin grading service for attribution and slabbing. However, anyone with variety coin submission experience knows the process is expensive and far from uniformly accurate. To approximate the probability that a presumptive doubled die variety coin will be attributed accordingly when submitted to a TPG service for attribution, I compared population count numbers from PCGS and NGC for two common date circulated grade Lincoln Cent doubled die varieties: 1917-P DDO FS-101 and 1934-P DDO FS-101. It is possible to draw potentially meaningful inferences from these comparisons for two reasons: 1. All coins submitted to PCGS or NGC for variety attribution must also be submitted for grading. 2. Few numismatic hobbyists would submit a common date circulated Lincoln cent for grading unless it was also being submitted for variety attribution. Because variety attribution is more difficult in the low circulated grades due to the additive effects of die state and circulation wear, I limited comparisons to coins that received a grade of at least VF20. Because some coins in the highest circulated grades may have been submitted only for grading if they were thought to be uncirculated, I limited comparisons to coins that received a grade of no higher than XF45. For all PCGS- or NGC-graded Lincoln cents grading VF20-XF45, it was assumed that the coins were originally submitted for variety attribution regardless of whether they were given a variety attribution. The probability that a presumptive variety coin would be attributed on submission was calculated as the total number of variety-attributed coins grading VF20-XF45 for a given year and mintmark divided by the total number of all coins grading VF20-XF45 for a given year and mintmark. Because the 1917-P DDO FS-101 Lincoln Cent doubled die is pretty obvious, a fairly high percentage of correctly attributed submissions was anticipated. In contrast, because the 1934-P Lincoln Cent DDO FS-101 has a secondary doubled die image that is very weak or worn away in late die stages or with heavy circulation, the percentage of correctly attributed submissions was anticipated to be fairly low. 1917-P LINCOLN CENTS At PCGS, among all 1917-P Lincoln cents grading VF20-XF45, there were 90 with a DDO FS-101 designation and 56 with no variety designation. So, for the 1917-P Lincoln Cent, 61.6% (90/146) of all submissions for grading received a doubled die variety attribution. This suggests that at least 61.6% of all presumptive 1917-P doubled die cents got the variety attribution from PCGS. If a few intermediate grade 1917-P Lincoln cents were submitted for grading only, the proportion of presumptively attributed doubled dies passing muster at PCGS could be higher. At NGC, among all 1917-P Lincoln cents grading VF20-XF45, there were 104 with a DDO FS-101 designation and 83 with no variety designation. So, for the 1917-P Lincoln Cent, 55.6% (104/187) of all submissions for grading received a doubled die variety attribution. This suggests that at least 55.6% of all presumptive 1917-P doubled die cents got the variety attribution from NGC. If a few intermediate grade 1917-P Lincoln cents were submitted for grading only, the proportion of presumptively attributed doubled dies passing muster at NGC could be higher. 1934-P LINCOLN CENTS At PCGS, among all 1934-P Lincoln cents grading VF20-XF45, there were 11 with a DDO FS-101 designation and 24 with no variety designation. So, only 31.4% (11/35) of all 1934-P Lincoln Cent submissions for grading received a doubled die variety attribution. For grades VF20-VF25 combined, 0% (0/11) of all submissions were attributed as doubled dies. At NGC, among all 1934-P Lincoln cents grading VF20-XF45, there were 9 with a DDO FS-101 designation and 102 with no variety designation. So, only 8.2% (9/111) of all 1934-P Lincoln Cent submissions for grading received a doubled die variety attribution. Report this Post to the Staff

PlutonianFire Valued Member United States 59 Posts	Posted 05/20/2025 05:46 am Some commentary regarding the above post. One thing that stands out is the similar proportions of all 1917-P Lincoln cents submitted to PCGS and NGC for grading that received a doubled die variety attribution. At PCGS, 61.6% of 1917-P Lincoln Cent submissions were attributed as doubled dies. At NGC, 55.6% of submissions were attributed. Using a one-tailed Z-test for the difference between two proportions, the difference was not statistically significant (p-value=0.13). In other words, the marginal 6% difference in proportions of doubled die attributions (61.6% vs 55.6%) between the two grading services can be considered to result from chance. Taking it further, if we assume the populations of collectors submitting 1917-P Lincoln cents to PCGS and NGC for grading/attribution are comparable, then the proportion of all submissions attributed as doubled dies by each grading service can be considered to reflect the relative strictness of criteria used for attribution For example, in the extreme, if say 100% of presumptive 1917-P Lincoln Cent doubled die variety submissions to NGC received the attribution but only 20% of submissions to PCGS were attributed, one could reasonably infer that attribution criteria at NGC were much more lax than at PCGS. It is also possible that some of that difference might be due to differences in the experience and proficiency of attributors at PCGS and NGC. However, the lack of any statistically significant difference in the proportion of 1917-P Lincoln Cent submissions attributed as doubled dies suggests that there is no meaningful difference in the attribution criteria (and competence of attributors) at PCGS and NGC. I qualify this with the caveat that my calculations are based on multiple unproven assumptions. Nevertheless, this may be a starting point for others to refine the algorithm. Report this Post to the Staff
tropicalbats Pillar of the Community United States 6047 Posts	Posted 05/20/2025 10:29 am Ask yourself why there are 881 coins dated 1969-S and graded PCGS between XF40 and AU58, and then think about whether it is the TPG missing an attribution or whether most of those submitted coins without attributes are submissions by folks thinking they had something they didn't. Report this Post to the Staff
J-Tal Valued Member United States 93 Posts	Posted 05/20/2025 10:52 am Looking at the 1975 philly strike dime is seems lots of people like to submit circulated coins in VF-AU Report this Post to the Staff
PlutonianFire Valued Member United States 59 Posts	Posted 05/20/2025 3:52 pm Quote: Ask yourself why there are 881 coins dated 1969-S and graded PCGS between XF40 and AU58, and then think about whether it is the TPG missing an attribution or whether most of those submitted coins without attributes are submissions by folks thinking they had something they didn't. I never said anything about TPGs missing attributions. I pointed out that in a hypothetical extreme case scenario where all submissions at one grading service were attributed but very few submissions at another grading service were attributed, the most likely explanation would be differences in the criteria used for attribution. For the sake of completeness, I mentioned that differences in the experience and proficiency of attributors could also factor in. However, the whole point of my post was to show that it may be possible to ballpark the probability that the average collector who submits a coin to a TPG for a particular variety attribution is going to get it right. For the conspicuous 1917-P Lincoln Cent doubled die, more than half of all collectors (55%-60%) appear to get it right. However, for the less obvious 1934-P Lincoln Cent doubled die, only a minority of collectors appear to get the presumptive attribution right. As you correctly point out, with an very rare and extremely valuable variety the number of collectors who presumptively make the attribution correctly is going to tank down into oblivion. In this case, I think many collectors probably realize their attribution is incorrect but the reward is so great if it is correct they are willing to pay a few bucks just for the thrill of "throwing their hat into the ring", so to speak. Report this Post to the Staff
Brandmeister Pillar of the Community United States 4696 Posts	Posted 05/20/2025 5:06 pm First, I applaud your efforts to make estimates on an esoteric subject like variety coins submissions. I also appreciated that you spelled out your thinking behind the estimates. At various points, I found myself at odds with some of the assumptions, but the framework itself is a great start. Will this be a paper at some point? It reads like a research submission. Quote: 2. Few numismatic hobbyists would submit a common date circulated Lincoln cent for grading unless it was also being submitted for variety attribution. Based on the sheer avalanche of common date sub-MS coins in PCGS slabs, I find this assertion hard to swallow. If we are to accept the premise that numismatic n00bs are specifically bombing variety attributions, I think there needs to be a comparison against equally common date/mintmark coins that have no major varieties. Quote: This suggests that at least 61.6% of all presumptive 1917-P doubled die cents got the variety attribution from PCGS. If a few intermediate grade 1917-P Lincoln cents were submitted for grading only, the proportion of presumptively attributed doubled dies passing muster at PCGS could be higher. I believe the second sentence to be a workable premise, but the first is not. The number of circulated common date grading-only submissions for other years must be considered. Those numbers are far above zero, even for high mintage year and mintmark pairings with no viable variety attributions. I think it would be more reasonable to develop a typical distribution based on a cluster of year/mm pairings with comparable mintages, then subtract that distribution from your variety year/mm under analysis. That could yield a better approximation of the collectors submitting for variety attributions beyond just the noise. I do happen to think that there is probably a large Red Book effect for varieties with separate entries. When people see those, they get really excited that the ordinary coin they just found in pop-pop's change jar is a rare numismatic jewel. I also happen to think that PCGS and NGC know the precise numbers for rejected variety attributions, and there is a snowball's chance in Hades that they will ever release those numbers. Report this Post to the Staff
PlutonianFire Valued Member United States 59 Posts	Posted 05/21/2025 09:47 am Quote: I think there needs to be a comparison against equally common date/mintmark coins that have no major varieties. Thank you for your thoughtful feedback. You are absolutely right about relatively large numbers of common date Lincoln cents submitted for grading in mint years where there is no well known variety. For example, there were 31 PCGS-graded 1916-P Lincoln cents in grades VF20-XF45 and 29 PCGS-graded 1918-P Lincoln cents in grades VF20-XF45. However, the total of 56 PCGS-graded 1917-P Lincoln cents without a DDO attribution in grades VF20-XF45 is far higher. The relative "excess" of 1917-P submissions, compared with 1916-P and 1918-P, is probably a good indicator of the number of 1917-P Lincoln cents submitted for both grading and variety attribution that did not get the attribution So, I am revising the above algorithm (from prior posting) to calculate the approximate number of 1917-P Lincoln cents submitted for both grading and variety attribution by subtracting the average number of 1916-P and 1918-P Lincoln cents submitted for grading from the total number of 1917-P Lincoln cents submitted for grading that do not have a variety attribution, and adding the number of 1917-P Lincoln cents that were graded and also had the DDO variety attribution.. This indicates that 26 of the 1917-P Lincoln cents were submitted for both grading and variety attribution but were graded without the variety attribution (56 - (31 + 29)/2 )= 56 - 30 = 26. Since there were 88 1917-P Lincoln cents grading VF20-XF45 that were given the doubled-die variety attribution, this suggests that 88/(88 + 26) = 88/114 = 77.2% of collectors were correct in their presumptive assessment. Report this Post to the Staff
Brandmeister Pillar of the Community United States 4696 Posts	Posted 05/21/2025 11:05 am My gut reaction to 77% is that it's a high number. That's just based on the number of stubborn rookies who pass through these forums who insist they will submit to PCGS against all well-intentioned advice. One possible source of error here is the Details grade. Rookies have a hard time detecting damage, scratches, and particularly cleaning. 1917 might have a relatively large graveyard of Details variety submissions (both successful and unsuccessful) that are outside the bounds of your grade limits. Report this Post to the Staff
PlutonianFire Valued Member United States 59 Posts	Posted 05/21/2025 12:12 pm Quote: One possible source of error here is the Details grade. Rookies have a hard time detecting damage, scratches, and particularly cleaning. 1917 might have a relatively large graveyard of Details variety submissions (both successful and unsuccessful) that are outside the bounds of your grade limits. That's an excellent point. In the population counts given by NGC, separate numbers are shown for Details coins and "nonDetails" coins. I was assuming that the population counts given by PCGS combined Details and "nonDetails" coins. Otherwise, they wouldn't be much help for some older coins. However, I could be mistaken here. Report this Post to the Staff
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