OK, with the rash of DDO/DDR coins that have been posted lately, none of which have been DDO/DDR by the way, how rare would it be? Obviously either obverse or reverse doubled die is fairly uncommon, so how rare is it to have one with both doubled die obverse and doubled die reverse? I would think it would be quite the rarity.
They are usually threads by new collectors who don't even know what a True Doubled Die looks like! I have been calling their claims - DDO - Definitely Damage Obverse and DDR - Definitely Damage Reverse! True DDO and DDR at the same time are uncommon. I once thought it was impossible until a CoinTalk member showed me a attributed and certified slabbed example.
There are a handful of known examples, mostly minor, of course, and much less common than one-sided varieties.
Presuming die doubling is a random event, then I would guess the odds of both sides would be the square of the odds of either one side. Ie, if a DDO is 1/1000, then a DDO/DDR is 1/1,000,000. But I could be totally wet here, that's just my intuition
I figured the odds of a doubled obverse die being paired with a doubled reverse die would be pretty slim. I'm not going to try to do the math though! Thanks guys, pretty much confirmed my guess.
Great minds think alike! Seriously though, if I had to guess it's likely well over or into the hundreds per one.
