I think the issue of marginal impact, particularly for relatively small donations going to organizations with rather large budget/​granting power, is quite difficult to be confident in, and hence shouldn’t be the driving factor in looking at the benefit of said donation. Much of the problem is illustrated well in Budolfson’s and Spear’s essay, The Hidden Zero Problem.
It does seem that many EA calculation rely on one of Parfit’s ‘share of the total’ errors that he outlined in Reasons and Persons, making transparent advertisement about the effectiveness of individual donations quite difficult.
I think the issue of marginal impact, particularly for relatively small donations going to organizations with rather large budget/​granting power, is quite difficult to be confident in, and hence shouldn’t be the driving factor in looking at the benefit of said donation. Much of the problem is illustrated well in Budolfson’s and Spear’s essay, The Hidden Zero Problem.
It does seem that many EA calculation rely on one of Parfit’s ‘share of the total’ errors that he outlined in Reasons and Persons, making transparent advertisement about the effectiveness of individual donations quite difficult.