Why are you paying full price, instead of trying to buy them at a discount? Or has that changed? Like let's suppose that each project you fund becomes 10% more likely because of the certificate scheme. In this situation, you should be trying to buy a certificate for the entire project at 10% of the altruistic value.
I disagree with your use of "should."
We also realized that the incentives were never going to be perfect or even great, once we had a dynamic process with more than one buyer.
Surely having multiple buyers improves incentive compatibility? In the limit consider the stock market, with a arbitrarily large number of buyers and very well aligned incentives.
Competition amongst buyers improves incentives in general, but the added complexity quickly destroys the specific guarantee of incentive-compatibility enjoyed by a second price auction.
For example, when the sale price in one round is published, it means that making a cheap sale can easily be worse than making no sale at all, since it affects what you might be able to earn in future rounds.
That's a particularly hard example to avoid. There are a bunch of other issues that seem easier to avoid, but only by placing increasingly strict constraints on the behavior of every buyer (e.g. once you make an offer on an item, you can never make any lower offer on the same item).
What's the deadline for submitting?
December 20, sorry for leaving that out of the original post.
The impact purchase has so far distributed $5k, out of $10k planned for 2015.
(If you don't know what the impact purchase is: the original announcement is here; my post on "certificates of impact" is here; Ben Kuhn posted a better explanation here; past results are here.)
We’re going to spend the final $5k in December. The last round is going to be significantly simplified, both for applicants and for us. Here’s how it will work:
As always, our evaluations will be unapologetically arbitrary, rough, and biased.
The idea that a fund outlay needs to be spent in haste since its completion date is approaching reminds me of the perverse incentives created in academic grants. What are your thoughts on simply rolling over the unspent money to increase the money you'll grant in 2016, rather than spending it in a hurry?
Several of the most promising applicants from previous rounds were willing to roll their applications to the new format. It's not clear that haste makes significant (any?) waste. We also weren't getting many new applicants per month without any new activity on our part, and we are generally interested in conserving time.
Since we never announced how much we would spend in 2016, it's hard to demonstrate that extra money is really extra.