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<p>[QUOTE=&quot;beef1020, post: 1213976, member: 24544&quot;]For large cents Dr. Sheldon, auther of Penny Whimsy, did an experiment to try to calculate survival rates of coins.&nbsp; I forget the specific details but do remember his estimate of survival was %3 or reported mintage.&nbsp; </p><p><br /></p><p>He took a specific die variety of large cents were there was a very good count of the number known to exist.&nbsp; Keep in mind the early date large cents have been collected by die variety for over 150 years, so these counts are surprisingly accurate.&nbsp; So, say a certain variety of 1794 large cents is known to have 60 examples.&nbsp; He would go to a dealer and ask them to put together a random lot of 1000 1794 large cents, which he would attribute and take a count of each variety he found.&nbsp; So if he found 2 of those variety, of which there are 60 known, out of 1000 coins then he estimated for each 500 coins you would find this variety.&nbsp; The total population would be 500*60 or around 30,000 total pieces.&nbsp; Except he did the same math for all the varieties he found and calculated the total population of surviving coins based on the known rarity of each variety.&nbsp; While each estimate was slightly different, the estimates did give very similiar results around 30,000 surving coins.&nbsp; Then he took a look at the total mintage of 918,521 1794 large cent and figured that around 3% survived.&nbsp; He redid the same experiment with different years and pretty consistently got an estimate of survival rates of around 3% of the reported mintage.&nbsp; So this is the number I use to estimate survival rates.&nbsp; </p><p><br /></p><p>I also use this estimate, along with ebay, to do crude comparisons of the reported rarity of varieties to determine what I think the rarity is.&nbsp; For instance, the reported rarity of the 1845 N7 large cent is R5 meaning 35-70 coins estimated to exist.&nbsp; I have checked ebay twice, about two months apart, for this variety and each time I search for 1845 large cent and ebay returns ~200 coins.&nbsp; Each time I have looked I find 1 unattributed example of this variety.&nbsp; With a mintage of 4 million and a survival rate of 3% there should be around 120,000 1845 large cent.&nbsp; This means I should find an 1845 N7, if 75 exist, about once every 1600 coins.&nbsp; I find one about once every 200 coins, which leads me to believe the rarity is grossly overstated, as once every 200 coins from a population of 120,000 coins leads to around 600 1845 N7 instead of the reported 75.&nbsp; I am not saying there are 600 of them, but the coin in my mind is not even close to R5.</p><p><br /></p><p>Edit, I guess it&#039;s worth noting that coin loss due to melting is much less of an issue with copper then it is with silver.&nbsp; So the 3% survival estimate may be right for early copper and too high for silver, but the same approach to estimating the current survival rate of any coin could be done.[/QUOTE]</p><p><br /></p>

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