The Universal Rarity Scale

One of the worst features of Numista is the seemingly arbritary nature of adding a "rare" tag to a coin. I have no idea who is doing this, whether it's one person or several, and please don't be offended whoever you are... but it really needs to stop. Seeing coins with mintages in the millions described as "rare" just gives the user an impression of some eBay dealer. What prompted this particular line of thought was seeing a coin with a mintage of 4,000 described as "ultra rare".  

On a couple of occasions now I have been involved with trades which included coins described as rare, or very rare. I can't help but feel uncomfortable wondering if the other party thinks I'm trying to cheat them by swapping a coin worth a lot of money. It's not something I would ever do, I take great pride in being scrupulously honest but I don't think I should have to explain the difference between a rare coin and one which is merely scarce. If I WAS trying to scam people out of rare coins, well that's what I would be saying isn't it!!

One of the greatest strengths of Numista is it's amateurish charm. We are not too serious and by and large free of the ego battles and acrimony of the larger coin forums. There are many members here who although I have yet to actually meet them, I regard as friends... good solid people and very enthusiastic collectors. Where else can you make such contacts?

So, having hopefully established that my intentions are good I will return to the subject at hand. There are two widely accepted measures of rarity. The first and most popular is the Sheldon Rarity Index, developed by the same guy who gave us the ghastly Sheldon grading System. The Sheldon Index is no use to us here at Numista. It has a total of 8 grades R1-R8 with R8 being a unique coin and R8 having more than 1,250 examples. So, the ultra rare coin alluded to above with a mintage of 4,000 wouldn't even register on the Sheldon Scale. As most, or more likely all, of the members here are not in the market for coins worth many thousands of dollars, the Sheldon Scale has no use for us.

However, I would seriously recommend adopting the Universal Rarity Scale (URS) as it is a much more relevant scale.

URS-0 None known
URS-1 1 known
URS-2 2 known
URS-3 3 or 4
URS-4 5 to 8
URS-5 9 to 16
URS-6 17 to 32
URS-7 33 to 64
URS-8 65 to 125
URS-9 126 to 250
URS-10 251 to 500
URS-11 501 to 1,000
URS-12 1,001 to 2,000
URS-13 2,001 to 4,000
URS-14 4,001 to 8,000
URS-15 8,001 to 16,000
URS-16 16,001 to 32,000
URS-17 32,001 to 65,000
URS-18 65,001 to 125,000
URS-19 125,001 to 250,000
URS-20 250,001 to 500,000

It should be noted that rarity indexes don't simply tally mintage figures which are often inaccurate or in some cases not even available. It is an estimate of the numbers of examples still surviving. However for our purposes the mintage estimates would work as it's not likely that anyone is going to be offering to swap anything from the top half of the index.

So, what do y'all think about adopting a simplified version of the URS to present a uniform, relevant and accurate indication of a coin's rarity?

Honestly, I think this a great idea. For me, I find it more accurate/appropriate than the current system. The only problem would be when there are no mintage numbers available... we would have to guestimate somewhat.

Thanks for this idea, Phil. About that Swiss Rappen we swapped. That was labelled as rare, but as you say it is a scarce coin. Is that right?
As I'm currently mostly collecting Swiss coins, the Swiss Mint has a number of mintage low moments creating scarce dates but do not come near the URS scale. Looking at the prices given on NGC these coins are highly valued, what would you suggest here?
Furthermore, I would like to see this implemented and offer to help on the Swiss coins if we are given the green light for this idea.

This isn't the same 5 rappen ? If it is all I can say is LOL

I am totally in support of what Phil has been describing, and thanks for the effort.

... and if I would be a teammember I would grab Phil's article and move it to Numisdoc, as it will be disappearing from here in some weeks, and he'll need to rewrite it again and again...
Because, I think - I am not sure - that educational articles shall go there.

Thanks fellers.

Yes, Swiss and German Emprie coins are where the problem is most noticeable. I'm sure there are other series where this occurs but you tend to notice the ones you actively collect.

Rarity scales work best when applied to a particular series, for example a great deal of research has been done on the current population of US large cents and UK pre decimal pennies. So when comparing the relative values of the 3 key date pennys, 1950, 1951 and 1953 the results are pretty accurate. The first two would be firmly at the lower end of the rarity index while the 1953 with an original mintage of 1,308,000 would fall outside and be more accurately described as scarce. This matches my own experience and I'm comfortable with it.

Where things start to go wrong is when you factor in demand and country size. It seems inevitable that a country with a relatively small population such as Switzerland will produce far smaller mintages than France, England or Germany. Look at the mintage figures fom 5 Franken coins! The Baltic States produced some very nice coins with low mintages but as there is little demand from collectors their values are relatively low. Most of the spurious modern commemoratives have very low mintages, sometimes just a few thousand but they are still pretty worthless despite being close to the top of the rarity scale. A scare coin from the US or UK will have far greater value than a genuinely rare coin from say Costa Rica. The point being that rarity does not equal price, it is merely one of several factors which influence it.

Citação: imrehI am totally in support of what Phil has been describing, and thanks for the effort.

... and if I would be a teammember I would grab Phil's article and move it to Numisdoc, as it will be disappearing from here in some weeks, and he'll need to rewrite it again and again...
Because, I think - I am not sure - that educational articles shall go there.

I am in total agreement with imreh on both fronts. The URS is an excellent idea, a very useful tool and more relevant than the Numista Rarity Index. However, I would still like to keep the NRI just for its curiosity value and to see how it compares the the URS. Also, as imreh suggested, I would urge the team to either copy Phil's article into Numisdoc or invite our esteemed friend to write a new one specifically for that purpose.

Citação: pnightingaleOne of the worst features of Numista is the seemingly arbritary nature of adding a "rare" tag to a coin. I have no idea who is doing this, whether it's one person or several, and please don't be offended whoever you are... but it really needs to stop. Seeing coins with mintages in the millions described as "rare" just gives the user an impression of some eBay dealer. What prompted this particular line of thought was seeing a coin with a mintage of 4,000 described as "ultra rare".

I share your pain, brother, it really makes me squirm when I see that on a coin page - any personal comments regarding the rarity or otherwise of a particular coin should be banished. We should leave our sensible membership to decide for themselves whether a coin is rare or not, based on the mintage data and aided by the Universal Rarity Scale.

Citação: pnightingaleOne of the greatest strengths of Numista is it's amateurish charm. We are not too serious and by and large free of the ego battles and acrimony of the larger coin forums. There are many members here who although I have yet to actually meet them, I regard as friends... good solid people and very enthusiastic collectors. Where else can you make such contacts?

My sentiments entirely!

Ah, yes. I wasn't implying that the Numista Rarity Index should be replaced. I think it's a great tool as it refers particularly to availibilty on THIS site. There is an option for whoever is adding a new coin to the database to include a comment and this is where things are getting confusing.

I've been adding a few coins earlier today, many of them with a mintage of less than 500,000 which would put them firmly on the URS. However they were mostly Caribbean and post-colonial African coins where small mintages are the norm so Ifelt it would be stretching the envelope a little to describe them as rare or even scarce.

I did however add one genuinely rare coin:

https://en.numista.com/catalogue/pieces1132.html

I used the comments field to include the grade, rarity and Krause value. I've seen several other collectors doing this and I think it's a great idea as it makes calculating a fair swap much easier. I just wish I had done this from the beginning, 6,000 coins is a lot to look up! Good job I've retired recently :)

I agree with the adoption of the universal scale for rare coins! It'll be a more trustee way and accurate as well. It's not that I'm against the Numista one but it's like wikipedia, anyone can add into it and put whatever they please  

Rarity = number of users wanting a coin minus number of users who own the coin?

Citação: CeruleanRarity = number of users wanting a coin minus number of users who own the coin?

That would be cool, except I didn't see any change in the rarity index numbers when we got the want list feature.

I've recently added some coins that have lowered to 93 on the rarity index

Citação: Mark240590I've recently added some coins that have lowered to 93 on the rarity index

I see a couple I would really, really like.

Citação: CeruleanRarity = number of users wanting a coin minus number of users who own the coin?

Now that's an interesting point, but the statistician (which we all appreciate) in you is showing......

What you are describing is fair market value (FMV) which adjusts for inflation, disposable income, precious metal values, collecting tastes, old collectors retiring and young people taking up the hobby (hopefully).

A coins rarity however, becomes fixed at some undefined point, presumably once it disappears from circulation. I guess it's conceivable that a circulating coin could be rare if you include errors and minor varities? Once a coin becomes vintage and is removed slowly from the currency pool or is demonitized and melted down by the gubbermint, it's numbers ought to remain largely static.

I guess that's a good illustration of the difference between rarity and price.

At this point I am tempted to speculate on what the US election's impact will be on coin prices but I think my dear friend Ben would not like it.

Citação: pnightingale

Citação: CeruleanRarity = number of users wanting a coin minus number of users who own the coin?

Now that's an interesting point, but the statistician (which we all appreciate) in you is showing......

What you are describing is fair market value (FMV) which adjusts for inflation, disposable income, precious metal values, collecting tastes, old collectors retiring and young people taking up the hobby (hopefully).

A coins rarity however, becomes fixed at some undefined point, presumably once it disappears from circulation. I guess it's conceivable that a circulating coin could be rare if you include errors and minor varities? Once a coin becomes vintage and is removed slowly from the currency pool or is demonitized and melted down by the gubbermint, it's numbers ought to remain largely static.

I guess that's a good illustration of the difference between rarity and price.

At this point I am tempted to speculate on what the US election's impact will be on coin prices but I think my dear friend Ben would not like it.

Nicely!