"[W]e spent approximately $100,000 on podcast ads during giving season (November and December 2017). Using the same methodology described above, we tracked $89,551 to our recommended charities as a direct result of these ads between November 20th and January 22nd. We estimate these donors as having a five-year, net present value of $250k-$410k." (GiveWell blog, Update on our work on outreach, December 19, 2017, updated January 25, 2018)
The returns we measured to our second year of podcast advertising (2018) were significantly lower than in 2017. We guess that this was in part due to the rising cost of ads and the greater number of podcast ads being run (thus potentially watering down the impact of any given ad), as well as our decision to run ads on expensive, well-known podcasts that ultimately had low returns. We hope that having better tracking in 2019 will give us better insight into this question.
 "We know that donors love donation matching.* We know that if we could offer donation matching on gifts to our top charities this giving season, our money moved would rise. And we know that we could offer donation matching if we thought it was the right thing to do: there are donors planning six-figure gifts to our top charities this year who would almost certainly be willing to structure their gifts as 'matches' if we asked. (It might not be possible to 'match' all of our money moved, but we could almost certainly provide 'matching' for a short period, which would motivate people to give during that period and would also provide us with some data on the impact of matching on our audience.)
"But we’ve decided not to do this because we would feel dishonest. We’d be advertising that you can 'double your gift,' but the truth would be that we just restructured a gift from a six-figure donor that was going to happen anyway. We’ve discussed whether we might be able to provide 'true' donation matching – finding a donor who would give to our top charities only on condition that others did – but not surprisingly, everyone we could think of who would be open to making a large gift to our top charities would be open to this whether or not we could match them up with smaller donors. Ultimately, the only match we can offer is illusory matching." (GiveWell blog, Why you shouldn't let "donation matching" affect your giving, December 15, 2011, updated July 25, 2016)
 "Influence matching. The matcher wishes both to support a particular charity and to encourage others to give to that charity. Therefore, the matcher makes a legitimate commitment to give only if others do, in an attempt to influence their giving." (GiveWell blog, Why you shouldn't let "donation matching" affect your giving, December 15, 2011, updated July 25, 2016)
 "GiveWell may offer donation matching sometime in the future. If so, we will be explicit about whether it is influence matching or coordination matching (we wouldn’t be comfortable offering illusory matching, except perhaps as a joke – i.e., 'If you’re thinking of giving to another charity just because of a donation match, let us know and we’ll get your donation to a top-rated charity matched'). If we do implement influence matching, it will be to (a) fully neutralize the effect of other matches on impact-oriented donors, further encouraging them to support the most impactful charities possible; (b) raise money from non-impact-oriented donors who are happy to have their donation 'matched' despite the logic above." (GiveWell blog, Why you shouldn't let "donation matching" affect your giving, December 15, 2011, updated July 25, 2016)