Liam:
Well, I'm clearly a stingy rater as all my deviations are where I have under marked compared to average.
Not as "stingy" as I am Liam!! Of my 842 ratings 734 are below the Community "average" and 110 of these have a deviation of .5 or greater.
I try very hard to rate the "site" rather than the "experience" unless I think the experience is typically poor because of the way the site is "shown". I note Daniel RF's 4.0 for the Canal du Midi (v my 2.0). If his boat had broken down, there had been terrible thunderstorms and he and his wife had split up during the "voyage" then, presumably, he would have marked the Canal rather lower???
As I said many years ago - we are rating these sites at a PhD level. they are supposed to be the "best of the best" in terms of their "Value"/"significance" etc. That calls into question both their rating within their "type" cohort and the rating of their "type" within all the types of heritage which are represented. (I.e how good a "mine" is it .... and how "good" a WHS can any mine be - even the "best"?) The WHC trend for granting inscription for "worse than average" sites isn't new and many such sites have found their way onto the list right from the start - e.g Madara Rider 1979 - one of 12 ratings of 0.5 I have given (though that was more likely due to lack of established standards and competition than political shenanighans)).
There is also the issue of "Granularity" - if everything is rated too highly there is no room left to differentiate (I think of "grade inflation" in the UK education system, and maybe elsewhere?) . I make 2.5 my "average" to give room for 5 "differentiations" above it and try to use ALL of the avaiable rating levels in a positively skewed normal curve.
Of course all such assessments are "personal". And we just have to look at the number of WHS which have been rated at both 5.0 AND 0.5 by different visitors here to demonstrate that. All any of us can try to do is to be
a. "Internally consistent" within our own values - difficult the more sites being rated and the look I have just given my current ratings shows me that a few are "out of internal line"!
b. Reasonably aware of the standards being applied elsewhere so that one can take stock and at least consider "re-calibrating" in some cases. Of course, like Meltwaterfalls, one might still conclude that the Bauhaus is at the pinnacle of WHS sites (I gave it 3.0!). I suspect that, like reading theatre. movie or opera reviews, we know by experience whose ratings we regard as the most "believable" in our "World view" and whose we just roll our eyes at and move on from!!
c. Open to re-evaluation if and when one learns more about a site even long after a visit. I perhaps haven't done that enough!!