Something you wrote in a comment further above:
This also entails accepting the Sadistic Conclusion, but that is an unavoidable part of all types of Negative Utilitarianism, whether they are of the normal variety, or the weird "sometimes negative sometimes positive depending on the context" variety I employ.
I don't think so, neither negative preference nor negative hedonistic utilitarianism implies the Sadistic Conclusion. Granted, negative utilitarians would prefer to add a small population of beings with terrible lives over a very large beings with lives that are almost ideal, but this would not be a proper instance of the Sadistic Conclusion. See the formulation:
The Sadistic Conclusion: In some circumstances, it would be better with respect to utility to add some unhappy people to the world (people with negative utility), rather than creating a larger number of happy people (people with positive utility).
Now, according to classical utilitarianism, the large number of happy beings would each be of "positive utility". However, given the evaluation function of the negative view, their utility is neutral if their lives were perfect, and worse than neutral if their lives contain suffering. The Sadistic Conclusion is avoided, although only persuasively so if you find the axiology of the negative view convincing. Otherwise, you're still left with an outcome that seems counterintuitive, but this seems to be much less worrisome than having something that seems to be messed up even on the theoretical level. You say you're okay with the Sadistic Conclusion because there are no alternatives, but I would assume that, if you did not yet know that there are no alternatives (you'd want to go with), then you would have a strong inclination to count it as a serious deficiency of your stated view.
Addressing the comment right above now:
How much harm should a negative preference utilitarian be willing to inflict on existing people to prevent a new person from being born?
Negative utilitarians try to minimize the total amount of preference-frustrations, or suffering. Whether this is going to happen to a new person that you'll bring into existence, or whether it is going to happen to a person that already exists, does not make a difference. (No presence-bias, as I said above.) So a negative preference utilitarian should be indifferent between killing an existing person and bringing a new person (fully developed, with memories and life-goals) into existence if this later person is going to die / be killed soon as well. (Also note that being killed is only a problem if you have a preference to go on living, and that even then, it might not be the thing considered worst that could happen to someone.)
This implies that the preferences of existing people may actually lead to it being the best action to bring new people into existence. If humans have a terminal value of having children, then these preferences of course count as well, and if the children are guaranteed perfect lives, you should bring them all into existence. You should even bring them into existence if some of them are going to suffer horribly, as long as the existing people's preferences would, altogether, contain even more frustrations.
A similar question I have is, if a creature with an unbounded utility function is created, does that mean that infinite wrong has been done, since such a creature essentially has infinite unsatisfied preferences? How does negative preference utilitarianism address this?
You will need some way of normalizing all preferences, setting the difference between "everything fulfilled" and "everything frustrated" equal for beings of the same "type". Then the question is whether all sentient beings fall under the same type, or whether you want to discount according to intensity of sentience, or some measure of agency or something like that. I have not yet defined my intuitions here, but I think I'd go for something having to do with sentience.
Granted, negative utilitarians would prefer to add a small population of beings with terrible lives over a very large beings with lives that are almost ideal, but this would not be a proper instance of the Sadistic Conclusion. See the formulation:
When I read the formulation of the Sadistic Conclusion I interpreted "people with positive utility" to mean either a person whose life contained no suffering, or a person whose satisfied preferences/happiness outweighed their suffering. So I would consider adding a small population of terrible lives ...
Summary: The term 'effective altuist' invites confusion between 'the right thing to do' and 'the thing that most efficiently promotes welfare.' I think this creeping utilitarianism is a bad thing, and should at least be made explicit. This is not to accuse anyone of deliberate deception.
Over the last year or so, the term 'Effective Altruist' has come into use. I self-identified as one on the LW survey, so I speak as a friend. However, I think there is a very big danger with the terminology.
The term 'Effective Altruist' was born out of the need for a label for those people who were willing to dedicate their lives to making the world a better place in rational ways, even if that meant doing counter-intuitive things, like working as an Alaskan truck driver. The previous term, 'really super awesome hardcore people', was indeed a little inelegant.
However, 'Effective Altruist' has a major problem: it refers to altruism, not ethics. Altruism may be a part of ethics (though the etymology of the term gives some concern), but it is not all there is to ethics. Value is complex. Helping people is good, but so is truth, and justice, and freedom, and beauty, and loyalty, and fairness, and honor, and fraternity, and tradition, and many other things.
A charity that very efficiently promoted beauty and justice, but only inefficiently produced happiness, would probably not be considered an EA organization. A while ago I suggested to [one of the leaders of the Center for Effective Altruism] the creation of a charity to promote promise-keeping. I didn't claim such a charity would be an optimal way of promoting happiness, and to them, this was sufficient to show 1) that it was not EA - and hence 2) inferior to EA things.
Such thinking involves either a equivocation or a concealed premise. If 'EA' is interpreted literally, so 'the primary/driving goal is to help others', then something not being EA is insufficient for it to not be the best thing you could do - there is more to ethics and the good, than altruism and promoting welfare. Failure to promote one dimension of the good doesn't mean you're not the optimal way of promoting their sum. On the other hand, if 'EA' is interpreted broadly, as being concerned with 'happiness, health, justice, fairness and/or other values', then merely failing to promote welfare/happiness does not mean a cause is not EA. Much EA discussion, like on the popular facebook group, equivocates between these two meanings.*
...Unless one thought that helping people was all their was to ethics, in which case this is not equivocation. As virtually all of CEA's leaders are utilitarians, it is plausible that is was the concealed premise in their argument. In this case, there is no equivocation, but a different logical fallacy, that of an omitted premise, has been committed. And we should be just as wary as in the case of equivocation.
Unfortunately, utilitarianism is false, or at least not obviously true. Something can be the morally best thing to do, while not being EA. Just because some utilitarians have popularized a term which cleverly equivocates between "promotes welfare" and "is the best thing" does not mean we should be taken in. Every fashionable ideology likes to blurr the lines between its goals and its methods (is Socialism about helping the working man or about state ownership of industry? is libertarianism about freedom or low taxes?) in order to make people who agree with the goals forget that there might be other means of achieving them.
There are two options: recognize 'EA' as referring to only a subset of morality, or recognize as 'EA' actions and organizations that are ethical through ways other than producing welfare/happiness.
* Yes, one might say that promoting X's honor thereby helped X, and thus there was no distinction. However, I think people who make this argument in theory are unlikely to observe it in practice - I doubt that there will be an EA organisation dedicated to pure retribution, even if it was both extremely cheap to promote and a part of ethics.