At the beginnings of this site, when we started measuring ourselves, user @EnergyNumbers informed in a comment here in meta, that the metric "Visits per Day" shown in Area 51, is a median, not an arithmetic average. And we have since then used this information in interpreting this metric.
But is it? Starting yesterday we had one more "spike question", this one , which currently runs at $5k$ visits. And the Area 51 metric "Visits per day" shows a value of $1,599$, while 29 days ago it showed $1,404$. Although not impossible, this is not the behavior expected from a median, but from a mean... or from a short-sighted median.
I used the access I have to site-analytics, and compared with previous meta-posts of mine where I have captured the metric at various time-points. Results: it appears that the metric Visits-per-Day is a 7-day rolling metric. But sometimes it looks like it is a median (with the median calculated as the average of the middle value, and the value before it), while in others, it appears to be the arithmetic average of this seven-day interval.
So can somebody from SE clarify this please?
We' re economists, meaning that
a) we like very much using metrics
b) we abhor using metrics that we don't know exactly how they are constructed.
BY THE WAY:
Our 30-day rolling average for Visits-per-Day grows very happily: In October 1, 2015 it was $911$. In November 1, it was $1,340$ (+ $47\%$)
The 90-day rolling average was $644$ in October 1, and $933$ in November 1 (+ $45\%$).