It seems that for a cumulative goal (say, word count) the relevant point is the 'mean delta', which is presumably the average daily increase? Although could anyone clarify if it only counts days with datapoints, or are all days counted whether data was submitted or not?
I think that both "average delta on all days" and "average delta only on days with points submitted" would both be very useful to know.
Also, does "mean of all datapoints" have any meaning at all on a cumulative goal? I'm struggling to see it if so. Though all data is good to have, of course ;p
Edit: Just seen the tweet saying both means interpolate gaps in data, so they're effectively the mean of ALL days whether or not data was uploaded. Weirdly, this is the opposite of what I'd naively expect, but that might just be me. Still, this is super useful - great uvi!