"When the limiting resource is money it's quite clear that we should prioritize the uses where it goes the farthest. If there are three organizations that can distribute antimalarial nets for $5/each, $50/each, and $500/each we should just give to the first one."
I strongly disagree.
The organization that can provide for $500 each the broad seeding of ethical consideration to those getting the anti-malaria nets is far more important than just giving nets for $5 to someone who will live to become corrupt and destroy the local ecology.
Happiness requires 2 things: reasonably good health, and a broad sense of being grateful. Not grateful to something, but just feeling grateful. That's it.
People working rice fields are most often happy, but they have nothing material. They often have hardships and more frequently die, but while living they are most often happy (first hand experience).
But in helping people who seem in-need, broad ethical concern must also include ecological impacts. Promoting health in a region where the ecological systems are sensitive to human expansion, is counter productive. More people survive to have more children, more people in need, putting pressure on the local ecology, destroying bio-diversity...
Helping people who have no broad ethical concern is wrong; this promotes corruption (illegal allocation).
A general consequence of helping humans without ethical conscience, is future humans will not experience the stabilization provided by broad ecological diversity as pathogens have plague-like consequences because natural microbes won't be around to keep "evolving" pathogens in check to be consistent with a stabilized ecology.
This is why the melting of the methane permafrost is such a major concern. The balance of microbes globally will change and the plants and animals will be affected as a result; i.e. potentials for mass/global extinctions.
The Point: Every proposed prioritization of resources should include a negative feedback control system to ensure slow growth reflective of broad benefits and limiting negative consequences. Slow because the beneficial synergistic systems take time to form, while corrupt systems respond more quickly (requires little thought and planning). The result of a lack of negative feedback is a spike of resource utilization that depletes the broad resources available and broad damage results; i.e. lack of sustainability.
http://eliminate-all-corruption.pbworks.com/w/file/fetch/57641792/3Predicting_the_Future.pdf
Ethics is a measure of organization, and as such provides predictability. Happiness of others can then be supported by broad planning of the future, seeding beneficial opportunities; not simplistically acting in the present.
So the $500/each might be the far less costly solution overall.
When the limiting resource is money it's quite clear that we should prioritize the uses where it goes the farthest. If there are three organizations that can distribute antimalarial nets for $5/each, $50/each, and $500/each we should just give to the first one. Similarly, if I have $5 I could use it to have my electricity be generated by wind or I could use it to fund distribution of an additional antimalarial net. I can't spend that $5 on both, so I have to choose, and I choose based on which I think will do more good with the money.
When the limiting resource is happiness, however, prioritization comes less naturally. I could stop taking warm showers, take the bus instead of driving, spend less to donate more, go vegan, donate a kidney, not run fans in summer, or do any of a very large number of things to make the world better at some cost to me. The more I do, the better, but the less happy I am. If I chose options without looking at how they trade off my happiness against benefit to others it would be like choosing what clothes to buy based on how much I would enjoy wearing them and not considering how much they cost.
I also posted this on my blog