"Uncommon", "Scarce", "Rare" - What Exactly Do These Mean?

And depending on the number of remainders and the survival rates, stamps with a 2500 issue quantity might not be scarce at all. Scott RS14 one of the private die proprietaries had an issue of 2500. The company went out of business almost immediately and there are lots of remainders including full sheets and imprint strips of four. So it catalogs $90 and VF-S examples are very frequently found.

Note that I corrected the printing figures for Mexico #706 and C61, using the late Dale Pulver's Intro to the Stamps of Mexico, and the last two Follansbee auction catalogs.

In terms of survival rates, visit the auction catalog for Kelleher's Flagship Sale #698, May 2-4, 2017. One of the lots was 100 complete sets of the Mexico National University issues, in sheets and half-sheets, in pristine, post office fresh condition. A photocopy of the original sale receipt was included, from 1935. I've wondered how the lot, which went for $150,000 including buyer premium, may have affected the market.

If a buyer was willing to pay six figures plus premium, they almost certainly knew they could sell them all and make a profit. So it probably didn't affect it all that much.

I agree with Don that the use of terms like "rare" in seller descriptions is meaningless hype in the vast majority of cases. I also agree with Sinclair that there is a way to use these terms in a descriptively meaningful, though perhaps impressionistic, manner. I tend to keep in mind a scale based on number of items in existence (which can be known with greater or lesser precision) rather than how available an item might happen to be at a particular time in the marketplace. Thus for US One-Cent 1851 stamps I would describe #5 as rare, #6 as scarce, #8A as uncommon and #9 as common. I also think there is a place for "extremely rare" (such as the One-cent Z Grill) and "extremely common" (#65).

In Paro, Bhutan, there are souvenir shops specializing in "rare stamps". The stamps on sale were basically the same that one might find in packets, only more expensive.

I would consider a #9 as "fairly common" and a #24 as "common".

Don's point about folks using 'whatever marketing puffery they can', and rogdcam's point that 'there are over 6 million "rare" items on ebay right now but only 149 thousand "scarce" items' pretty much sums up the situation on ebay. I dare say some auction houses are guilty of this too, although it is heartening to know that some dealers and auction houses do try to be more objective by giving some data points (e.g. only 1 of 5 known etc).Then, this is only possible if someone has done all the hard work in compiling a comprehensive census that is recognised by the community (re: rod222's post about Australian Postmarks, with scarcity given to a scale of existence R to RRRRR depending on known numbers), but I wonder how many such works are there out there. Printing quality might be out there, but survival rates? Number of mint/used? Number on intact covers?

At the same time, I guess I have made things difficult for myself by confusing rarity with price and market demand. Thanks for highlighting that high price and market demand do not equate to rarity. It can be rare, but if the market demand is not there, a high price will not be supported (as evidenced by Scott catalogue values and auction realizations).

A collector showed his Bechuanaland Protectorate at my local stamp club.
He highlighted the rare items in red ink, and attached useful notes, detailing such things as "only example known", "largest known block", "one of three known" etc.
At the other extreme you have idiots on ebay claiming even common stamps from a tatty kiddies' album are 'rare'.

Scarcity without corresponding demand = merely "interesting" or "curiosity".

I have numerous items in my collection that are unique or are 1 of [single digits] known... most are worth a few hundred bucks at most. If they were front-of-book items, their values would be at least an order of magnitude higher. There's not the same level of demand for back-of-book.

Conversely, Zeppelins and dollar-value Columbians don't even rate as "scarce" let alone "rare" in my opinion. They're just expensive. I can walk into any decent sized stamp show and have my pick of numerous mint and used examples of any of them. All it takes is a checkbook.

They have demand and notoriety as "key items" in every collection. They're not actually hard to find at all.

To me, distilling down to a simple concept, sans impact of demand: "scarce" is an extant population of 2-3 digits. "Rare" is a population of single digits. That is an oversimplification, of course, but it will serve.

"Scarcity without corresponding demand = merely "interesting" or "curiosity"."

Part of the problem with this is that to some extent at least, cat value increases demand. So many double transfers are very scarce to rare, but they catalog nothing so no dealers actively look for them. If they find one marked, and they have some idea of their real scarcity they price them accordingly. But they rarely come up for auction unless they are the 1847, 1851, or 9X1 varieties. So a genuine value scale never occurs and most collectors never see them. So it remains a vicious cycle. No value, so no interest, so no value.

I seem to remember that Linn's once published a rarity chart but cannot put my hands on it now.

The British North America Philatelic Society, Society for Canadian Philately has rarity scales for three categories of Canadian philately: Registered Mail, Perkins and RPO's.
http://www.bnaps.org/rarity.htm

This leads me to believe that the definitions for rare, scarce, all the way to very common is dependent on what is being collected.

Therefore, I vote to make floortrader's definitions official, by law.

Germania, I second that motion and call for a vote.
Maybe the surviving copies of that Linns chart are scarce.

uncommon = I have more than 200 of these to sell

scarce = I think there are 50 of them in stock

rare = I have 10 or less on hand

I bought an item today that I would call rare with approximately 10 or less in existence. It may be be hard to believe but rare, scarce, or uncommon was NOT part of the description. It is the second one that I have purchased that did not employ any type of puffery.

I like what was done in "Simpson's U.S. Postal Markings 1851-61".

They use a scale of 1-10 as rarity numbers and they give a description that corresponds with each number. It's not based on any dollar value or market availability but on known numbers of copies.

1 = Extremely Common with over 100 copies known.
10 = Unique with one copy known.
And all ratings in between.

For example a New York 1853 Year Dated CDS is a 4 = Moderately Scarce.

A Randolph Macon College, Virginia CDS is a 9 = Extremely Rare.

The book I have is the second edition published in 1979. I don't know if there's an updated version with updated "rarity numbers". But I use this one as a "price guide" when buying or trading for covers.

Edit: Winston if the item you purchased was a postmark in Simpson's it would be rated a 7 = Rare with 7-10 recorded copies.