In reply to paul__in_sheffield:
> I guess he could mean the decline in average trad grade from HVS in the '90s to MVS now (based on the log boog data in UKC)
As I point out every time someone trots out those stats, they're conveniently accessible but probably pretty meaningless.
Firstly, because average grade tells you very little about what people are actually capable of climbing. My average grade from year to year tells you more about who I climbed with that year than my limits.
Secondly, because nobody was logging on UKC as they went along back at the start of your comparison, so very few people will have gone back and exhaustively logged everything. I'd imagine most just went back and logged a subset of routes that stood out for them or that they wanted people to know they'd climbed, which is almost certainly biased towards higher grades.
And finally, because people who are keen enough on climbing to be coming on UKC when it starts up and logging their routes from the 90s are probably not a particularly representative sample of all climbers from the 90s anyway.
I'm sure there are loads of other confounding factors as well. Given all of those complications in the data, HVS to MVS is a pretty small shift to be placing significance on.