I agree the double-counting issue is pretty complex. (I think maybe the “fraction of value added” approach I mention in the value of coordination post is along the right lines)
I think the key point is that it seems unlikely that (given how orgs currently measure impact) they’re claiming significantly more than 100% in aggregate. This is partly because there’s already lots of adjustments that pick up some of this (e.g. asking people if they would have done X due to another org) and because there are various types of undercounting.
Given this, adding a further correction for double counting doesn’t seem like a particularly big consideration—there are more pressing sources of uncertainty.
I agree the double-counting issue is pretty complex. (I think maybe the “fraction of value added” approach I mention in the value of coordination post is along the right lines)
I think the key point is that it seems unlikely that (given how orgs currently measure impact) they’re claiming significantly more than 100% in aggregate. This is partly because there’s already lots of adjustments that pick up some of this (e.g. asking people if they would have done X due to another org) and because there are various types of undercounting.
Given this, adding a further correction for double counting doesn’t seem like a particularly big consideration—there are more pressing sources of uncertainty.
Yes, I agree with this. (See also my reply to Rob above.)