| Author |
 Replies: 72 / Views: 10,978 |
|
Pillar of the Community
United States
721 Posts |
My little project for the day. This may have been done before, but I'd like to present my findings. I looked at mintage figures for the Lincoln cents 1909-2010. I divided them into the two traditional groups: wheats (1909-1958), and modern (1959-2010). I am not including varieties such as 1955 DD, 1960 small date, etc., since these have no specific mintage figures. I took the log (base 10) of the mintage figures and determined their statistical z-score. (The log value gave, in my opinion, more realistic z-score distributions than using the raw mintage figures.) The z-score is a measure that tells how many standard deviations it is above or below the mean. Key dates would have very negative scores. What I was trying to do is to see what z-scores are for the traditional key dates and then compare these values to the more modern cents.Here are the results for the LWC: 1909 S VDB -3.07 key 1931 S -2.71 key 1914 D -2.51 key 1909 S -2.25 key 1924 D -2.05 semi-key 1911 S -1.76 semi-key 1914 S -1.74 semi-key 1912 S -1.70 semi-key 1931 D -1.70 semi-key 1926 S -1.69 semi-key 1915 S -1.65 semi-key 1910 S -1.51 semi-key 1913 S -1.50 semi-key I used the definitions of key and semi-key from http://www.lincolncentresource.com/index.htmlUsing the cutoff value for a key date to be -2.2 or smaller and a semi-key between -2.2 and -1.5, I then determined the following for the modern cents and used this definition to label them as key or semi-key: (1959-2010): 1968 S -3.12 key 1973 S -2.87 key 1972 S -2.65 key 1974 S -2.55 key 1971 S -2.24 key 1969 S -2.20 key 1960 -2.10 semi-key 1962 -2.06 semi-key 1959 -2.06 semi-key 1970 S -1.90 semi-key 1961 -1.79 semi-key 1963 -1.79 semi-key It is interesting to note that WITHIN these groups, the 1968 S is comparable to the 1909 S VDB! You can make similar comparisons between the groups, such as the 1974 S is very comparable to the 1914 D. I know this is a long read and there are many interpretations, but I thought this was interesting. I also felt is was important to have the two groups of data span about the same number of years. I also know there are other variables to consider to determine what is a key date. Finally, there has been talk about how low mintage the 2009 cents have been. Here are the results of these: 2009 P -1.32 This compares best with: 1923 S -1.29 2009 D -1.17 This compares best with: 1932 D -1.17 Comments? Thanks for reading... Edited by drdave
05/21/2011 12:42 am
|
|
|
|
Pillar of the Community
Canada
838 Posts |
This is awesome work you've done! It's really neat to see the comparisons between wheats and memorials like this. I suspect the Zincolns will be tougher to obtain in higher grades than the Coppers; however, if a lot of copper disappears in 20 years, we might just have some of these memorial "keys" show themselves as such!
|
|
Pillar of the Community
United States
4000 Posts |
Interesting view. I was following you until I got to: Quote:
Finally, there has been talk about how low mintage the 1909 cents have been. Here are the results of these:
2009 P -1.32
This compares best with:
1923 S -1.29
2009 D -1.17
This compares best with:
1932 D -1.17
|
|
Pillar of the Community
Canada
838 Posts |
By the way, how about breaking 2009 down into LP-1,2,3,4, since mintages are available for those? Also, there are estimates on the variety mintages from circulation pulls. For these, follow the links on Clint's page (from Stanford U.) on U.S. Coin prices.
|
|
Pillar of the Community
 United States
721 Posts |
Scooby Due: The 2009 cents are relatively low mintage. I emphasize the word relatively. The 2009-P is comparable to the 1923-S, in terms of relative mintage within each of their groups. What I was trying to show is that the 2009-P is low mintage (1.1 billion) but it should be viewed in the same light as the 1923-S (8.7 million). The 1923-S is not considered a semi-key, but it does have a low mintage. We should view the 2009-P in the same way.
|
|
Pillar of the Community
United States
721 Posts |
bibd: breaking down the 2009 mintages would make their z-scores around -3, but I'm not sure that's a fair comparison.
|
|
Pillar of the Community
United States
4000 Posts |
Quote:
Finally, there has been talk about how low mintage the 1909 cents have been. So, you meant 2009 there, not 1909?  |
|
Pillar of the Community
United States
721 Posts |
OOPS - late night typing: "low mintage the 1909 cents have been", should have been 2009 cents!
I will edit my original post.
|
|
Valued Member
United States
397 Posts |
I'm curious about breaking down the 2009s as well. I pull LP1s all day long, but I almost never see an LP4. It's gotten to where I pull the LP4s if they're even the slightest bit shiny with no pits anywhere. Zinc rot is so fast I really think that in another 10 years or so you won't be able to find them in circulation at all.
|
|
Pillar of the Community
United States
721 Posts |
Here's the 2009 breakdown:
2009 P4 -3.05
2009 D4 -2.63
2009 P1 -2.26
2009 P3 -2.16
2009 D3 -2.10
2009 D1 -2.05
2009 D2 -2.02
2009 P2 -1.98
|
|
Pillar of the Community
Egypt
3470 Posts |
Very good work, well done  |
|
Rest in Peace
United States
9104 Posts |
OP-
I've always heard 65-66-67 and 69 cents being harder to find, yet they didn't make your list.
|
|
Rest in Peace
United States
4078 Posts |
Once again great information! Thanks.
|
|
Moderator
 United States
15381 Posts |
Great analysis! You know I am a fan of coin statistics. I'll read it again and think it through ... but enjoy the concept and methodology. Well done. David |
|
Valued Member
United States
103 Posts |
bibd, you made a comment regarding the disappearance of copper cents. Do you believe this will have the same effect on the value of these coins as it did on the silver coins?
|
|
Pillar of the Community
United States
721 Posts |
biggfredd: Here are the results for the 1965-1969 cents. I included the calculated z-score (not ranked). All but the 1969-D have negative values. There may be other reasons why certain coins may be hard to find in population; this is only one way to look at them.
1965 -0.94
1966 -0.47
1967 -0.06
1968 -0.78
1968 D -0.13
1968 S -3.12
1969 -1.28
1969 D 0.28
1969 S -2.20
So I would say they are less than average mintages, but the ones you mentioned would not be considered semi-keys.
|
| |
Replies: 72 / Views: 10,978 |
Posted 05/21/2011 12:22 am
