If the EA movement forces big charities to focus a bit more on bang for buck, then that's a win. Perfect efficiency will never be possible anyways.
But the follow-up studies seem far more important, than the per unit cost of mosquito nets.
Could you expand on this some more? The primary argument against utilitarianism I recall is the hypothetical situation of there being that gets infinitely happy if you donate to it, so that the maximally useful thing would always be to donate to that being (or something like that, but you get the gist).
But such a being does not exist, and if we accept that our utilitarian gifts are not going to be perfect, isn't it a reasonable assumption that by trying to maximise the amount of good that can be done for our bucks, on average, the amount of good that will be done for our bucks will be higher than if we did not approach it like that?
You are a doctor. You have four patients. Three are young men in otherwise good health who need an organ or they will die very soon -- two of them need kidneys and one of them needs a heart. Your fourth patient is a homeless person who's broken his leg but is otherwise well. You know for a fact he has no friends or family who will notice he is gone, and that nobody will know it if you kill him. Under a strict utilitarian framework, it is not only permissible but actually mandatory that you kill this man and harvest his organs to maximize utility.
Another popular one is a variant on the trolley problem. Most people feel it is morally permissible to change the switch on the train tracks to go toward the side with fewer people, even though it will lead to some people dying. Most people do not feel it is permissible to push someone (say in a car) in front of the train in order that they may stop the train while being killed in the process.
There are others of this genre but you probably get the basic idea. Utilitarianism can lead to plainly monstrous conclusions. I'm suspicious of any "formula" to solve all ethical problems.
Also, in your example of pushing someone in front of the train, wouldn't your moral intuition depend on the stakes? Suppose that the train not being stopped was going to set off a chain reaction that would kill all life on earth?
That depends on what utility function you're using.
I kind of think that society does use something like the measure of utility I described - we just don't talk about it a lot. For instance, doctors will refuse to do an operation on someone who is sufficiently old and frail. Courts will award less to an elderly victim of medical error. And so on.
Edit/post script: Also, I think you implicitly are assuming that utility is one dimensional, and that you can add up quality of life changes and balance them against lives ended. That does not necessarily seem valid or essential to some form of utilitarianism.
It seems that way to me. What difference does it make to utility whether a life ended naturally or unnaturally? Indeed, death from organ failure is probably much more painful than whatever I might do as an unethical doctor. Once you're looking at utility + non-utilitarian considerations like "murder is wrong," it's simply not utilitarianism anymore.
Since we're hung up on details, let's look at other examples:
* You're a judge in a frontier town with only a rudimentary justice system wherein the only possible punishment is hanging the accused person on the spot after they are found guilty. A townsperson is accused of witchcraft. You know this defendant is not guilty, because there is no such thing as witchcraft, but you are also certain that if you rule that the defendant is not guilty a riot will break out and several people will be killed. Therefore, the utility-maximizing option would seem to be falsely finding the defending guilty and ordering execution. Is that the ethical thing to do?
* You are preparing a body for burial. The body is to be buried with several pieces of precious jewelry, per the family's request. You know that if you steal the jewelry, replace it with costume jewelry, pawn the real jewelry, and use the funds to buy your friends dinner, nobody will be any the wiser, and you will have maximized utility by using the jewelry to bring your friends happiness rather than burying it. Ethical?
Edit/post script: I am not so sure that rules like "don't murder" are in conflict with utilitarianism as I think of it existing. Maybe if you look at moral choices as an optimization process, simple rules function as heuristics to deal with uncertainty, bias and lack of information on utility.
Right, I think that's what I'm mostly interested in - what if you treat utilitarianism as a guideline? If you only apply it in cases where you think most people would agree on what is "most useful", would that not lead to better decisions on average, without influencing potential hypothetical edge cases?
(I also happen to think that the most useful thing in your situations is to respect the law, and have the law say that you're not allowed to exploit the homeless person, since that also influences the amount of trust we have in other people and hence the quality of life, but that's probably less relevant for what I'm interested in now.)
I don't think the law thing works at all. Laws can be and often are unjust. Imagine I live in a twisted society where the doctor killing patients to harvest organs is legal. Is it now ethical? This is not purely theoretical -- the people operating concentration camps in Germany weren't violating German law.