In reply to tom_in_edinburgh:
> The trad system can't do that either e.g. you see a grade of E3 6b - the 6b bit tells you the crux is hard. You can't tell whether the E3 is because the crux is bold or because there is a very sustained bit of bold easy climbing or a second easier but badly protected crux higher up.
Yes it can! A bold crux after easier safe climbing would give you a different (higher) adjectival grade than a safe crux after easier bold climbing, whereas your grading system can't differentiate between these two. I can't imagine an E3 6b with a bold crux (6b is pretty hard for E3!).
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> Look at the maths. The trad system gives you a tuple <f(c, s, d), c> i.e. the adjectival grade which is some vaguely defined function of crux, sustained and danger followed by the actual value of crux. The idea being you can estimate d based on your knowledge of c. However even if you could cleanly reverse the combining function to 'subtract' c you'd still be left with a combination of s and d with no means of separating them.
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> The alternative is <f(c, s), d> i.e. the difficulty grade is a function of crux and sustained followed by the actual value of danger. The second system gives you a number for how hard it is to get up the route followed by one for how likely you are to get hurt trying
The problem here is that you are fundamentally failing (or refusing) to understand or acknowledge that the interaction between c, s and d is of substantive interest. Piling them all together therefore gives you some information about this interaction, whereas having them separate doesn't. Yes, unpicking them is non-trivial, but people seem to manage it pretty well on the crags every weekend. If your idealised climbing grade is <c, s, d> then I'm not sure even that's an improvement on the current system.
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> The force that will drive globalisation of climbing grades is the commercial pressure for guidebook publishers and internet databases to cover many countries and provide richer search functions to help people decide where to go. In the context of an internet database the more information captured in the grade the better.
I will happily wager you that there will be no 'Globalisation' of climbing grades in my lifetime. On a day-to-day level very, very few people face a choice of crags in multiple countries for their climbing that day. So cross-country comparability is not really a major problem. Perhaps you have a private jet, which is skewing your perspective somewhat?
You are trying to solve a problem that:
a) Barely exists
b) You appear not to understand very well
and c) The acceptance costs of any solution are very likely to far outweigh the benefits.