Quantitatively this seems to be where Price's law comes in:
The square root of the number of people does half the work. (Think of the matrix diagonal.) With three people in a group, 1.5 of them do half the work. With 10,000 in a group about 100 of them do half the work.
Price's law also seems to be recursive. Just like Pareto's 80/20-rule.
Also:
About every two orders of magnitude, the whole Geometry of the problem changes.
On the order of 100 people is very different from being on the order of 10,000 people.
There seems to have been an article on HN in the last few months that made a similar point related to building bridges of different lengths. About about every two orders of magnitude everything changed. A one inch bridge could be made out of spaghetti. A 2 yard bridge is different, a two mile bridge is different yet again. And a 100 mile bridge has to think about tectonics.
The square root of the number of people does half the work. (Think of the matrix diagonal.) With three people in a group, 1.5 of them do half the work. With 10,000 in a group about 100 of them do half the work.
Price's law also seems to be recursive. Just like Pareto's 80/20-rule.
Add Conway’s law to this and you are all set.