[ARC5] Scarcity Rating Scale Again

[David Stinson]

We've discussed this once before, but I thought I'd get
a more current sense of the ARC-5 community's ideas.

I believe a rating system should make clear distinctions
with clear definitions of each category, 
and be as simple as possible consistent with that goal.
I believe things like a "ten-step" scale are arbitrary;
what exactly is the distinction between 
a "7" and an "8" rating?

The current 5-step scale, which does not count
museum pieces because they are not available to 
collectors, works like this:

Extinct:  No examples known to have survived.
Unique: Only one known (prototypes, A.R.C. morgue).
Rare: Ten or fewer examples known.
Uncommon:  Difficult to find, meaning that diligent search
may uncover one, perhaps two pieces in a year of looking.
Common:  Easy to find.  

My concerns are:
The word "Uncommon-"  I don't like it; it's too close
to "common" but defines an important distinction.
Can't think of a better word that keeps the meaning.
Can you?

The "Uncommon" category itself.-
On the one hand, it paints with a fairly broad brush, 
since things like 3rd-Generation ATAs are more "uncommon" 
than SCR-274N transmitters, but are certainly not "rare."
On the other hand, a piece is either hard to find or it is not.
I don't see how to "split the sheets" within this category
without muddying the system with ambiguities.
Maybe, "Uncommon +"?

73 Dave S.