[quietbritishjim]

I was responding to what you said in your original comment:

> Whatever number you come up with, treat it as the median ...

Especially the "whatever number you come up with" bit, which seems aimed at everyone quite generally. When people usually come up with a number, it is likely to be a substantial underestimate. This isn't just a cognative bias where I've forgotten the times the task turned out to be simpler - evidence shows this to be the general trend (a la Thinking Fast and Slow, as I mentioned in another comment). So your rule that it should be treated as a median isn't correct in the majority of cases.

> these numbers ... comes from studying vast amounts of high quality ... data

Well that's a different matter. Of course, whether the result of analysing that data is a median or a mean (or something else) depends on how exactly you analysed it.