What would count as progress
A method that produces counterfactual estimates for ordinary gifts, with error ranges, at a cost small relative to the gift.
Why it matters
The real effect of a gift is the difference between the world with it and the world without it. Most givers never see that difference, which is part of why the feedback loop is missing.
Where to start
Funding-gap disclosures (how much a charity could productively absorb), matched comparisons between funded and unfunded applicants, and published “room for more funding” analyses are partial answers. The open problem is making them routine.