general question on grading world coins

Forn coin grades are stricter than the US. Many coins we would call unc only rate xf elsewhere.

Numerical grades seem to provide something that doesn't exist.

There's a big difference between accuracy and precision.

Numerical grades promote the illusion that a MS62.47 is provably better than a MS62.35, and that we can discern the difference to two places past the decimal point.

The problem arises where even if one TPG could consistently make such distinctions (they can't--see crack out), a different TPG may come up with a completely different number.

One famous coin (1913 V, IIRC) ping ponged between NGC and PCGS over the years, gaining 20 points in the process.

What I'm thinking of doing is trading off my world coins, ideally for US 90% or to fill holes... was trying to assess the value of them but quickly realized I am not up to the task.

What I'm doing instead is picking out anything with a value per coin of $5 or more in XF condition...I'll list them, if I get someone interested THEN we'll negotiate on what the appropriate grade/value/etc might be.

The Krause catalogues are printed in America by an American company, so they use American grading standards; in theory, an "EF" in Krause for a world coin should mean the same as an EF for an American coin. Though sometimes, the valuations supplied to Krause by their informers and contributors are based on local grading systems.

As for the question, "What to do about coins in "in between" grades", if you don;t have a specialist coin catalogue from that country, then the only answer is to wing it. If I particularly need to assign a book value to an aUnc coin, I take a guess at about 1/3 of the distance between EF and Unc for a typical circulation coin series, perhaps halfway for NCLT or other series where Unc coins are relatively common.

Or, if you want to get all mathematical, plot the prices for VF, EF and Unc as a curve on a graph, and interpolate a price on the curve halfway between EF and Unc. Not sure the number you'd get back would be much more reliable than a guess.

@SAP-
What are the European grades and definitions? Is there no AU grade in the European system?