In reply to planetmarshall:
Once you have the data the calculations are really fast, it's the database access that kills you. This set of numbers is a little bit out of date but gives an idea of just how bad hitting the disk or network is if you want to keep things moving:
https://gist.github.com/hellerbarde/2843375
For people who don't think in nanoseconds there's a "humanised" version if you scroll down a bit.
Of course UKC is built on a database so in a sense that horse has gone
On the question of "what we want average grades to mean", yeah. A specification problem!
Personally I think mean is the wrong choice because the average you get depends on exactly how the grades have been subdivided and had numbers assigned. A system that has D,VD,HVD,MS,S will not give the same answers as one that has D,VD,HVD,S etc. A median is less sensitive to such things.
In reply to apwebber:
Yeah you could do it when you generate the graphs easily enough. My point was that running means are really, really easy to update as you add climbs to the database. Comments about the natural laziness of software developers would have been both ungracious and a clear case of projection on my part.
Post edited at 09:14