Can't say I've seen specific models. I imagine it depends on what the utility functions of charities are. If the charities are run by people just looking to keep their jobs/get status, I'd guess they want people to donate to them rather than other charities on the margin, and that would lead to people donating to lots of charities. If charities just want to help make the world better then that implies that they want people to donate to the single best charitiy. Since there are many charities in the world, that supports theory 1.
I don't think it depends on the motivations of those in the charities, based on my views of the insides of a few - some of which had succumbed thoroughly to the Iron Law of Institutions (where the people working there didn't believe any more), some of which were pretty solidly oriented to their stated purpose, and some of which were in between (some recoverable, some not).
I think we can reasonably just assume, without making this question meaninglessly hypothetical, that the charities want money and we don't need to go more deeply into it for the question ...
Reposted from a few days ago, noting that jsalvatier (kudos to him for putting up the prize money, very community spirited) has promised $100 to the winner, and I have decided to set a deadline of Wednesday 1st December for submissions, as my friend has called me and asked me where the article I promised him is. This guy wants his god-damn rationality already, people!
My friend is currently in a potentially lucrative management consultancy career, but is considering getting a job in eco-tourism because he "wants to make the world a better place" and we got into a debate about Efficient Charity, Roles vs. Goals, and Optimizing versus Acquiring Warm Fuzzies.
I thought that there would be a good article here that I could send him to, but there isn't. So I've decided to ask people to write such an article. What I am looking for is an article that is less than 1800 words long, and explains the following ideas:
but without using any unexplained LW Jargon. (Utilons, Warm Fuzzies, optimizing). Linking to posts explaining jargon is NOT OK. Just don't use any LW Jargon at all. I will judge the winner based upon these criteria and the score that the article gets on LW. Maybe the winning article will not rigidly meet all criteria: there is some flexibility. The point of the article is to persuade people who are, at least to some extent charitable and who are smart (university educated at a top university or equivalent) to seriously consider investing more time in rationality when they want to do charitable things.