How should we compare the impact of various outcomes, such as improving health or reducing poverty, in terms of how much good they do?
The current method used by effective altruists relies on subjective judgements; the value of different outcomes are weighed in the mind. Health metrics such as QALYs and DALYs, which rely on other people’s aggregated subjective judgements, are often used. However, health is not the only item of interest and subjective judgements are still needed to decide how the value of health outcomes should be compared to other outcomes.
The charity evaluator, GiveWell, determines the value of different interventions by polling their staff members. This is explained in more detail in their cost-effectiveness analysis. The main question in their analysis is “how many years of doubled consumption are as morally valuable as saving the life of an under-5-year old child?” GiveWell uses the median answer to establish the trade-off ratio between these two outcomes.
We might think that relying on our subjective judgements is both unobjectionable and unavoidable on the grounds we are making moral evaluations, and there is simply no other way to do this. However, the claim these are moral judgements is only partly true and, indeed, may not be true at all. Some of what appear to be moral evaluations are judgements about facts and so, in principle, empirical questions.
Facts and values
Here’s an analogy. Suppose you and I are trying to determine which of two oddly-shaped jars contains the most water. What sort of assessment are we making here? Not a moral judgement, but a subjective judgement of fact. We could go on to say the best jar is the one that holds the most water, which would be a moral judgement.
Now, suppose you and I are trying to assess which of two outcomes increases happiness the most: curing health condition A or alleviating poverty by amount B. Suppose we agree on our concept of happiness: a positive balance of enjoyment over suffering. Are we making a moral evaluation when we state which outcome we think would increase happiness more? Clearly, as the jar analogy showed, we are not. We need not assume happiness is of any moral importance - perhaps we conclude only liberty has value - to compare the outcomes.
By contrast, deciding (a) which thing or things are intrinsically valuable and thus constitute the good(s), and (b) how to aggregate the good(s) to determine overall value (in philosophical jargon, an axiology - the method of ranking states of affairs in terms of their ultimate value) is, certainly, a moral judgement.
Suppose, for example, we decide the value of an outcome is the sum total of happiness in it. That is a moral judgement. However, now we’ve taken that as given, determining how much good an outcome contains is, in principle, an empirical question. Those will be judgements of fact, not of value.
I hope it’s obvious that we will, where possible, want to measure the good(s) directly, and that objective measurement of the facts ‘trumps’ our subjective evaluations of the facts. If we could measure the water capacity of the jars, there would be no need to guess.
If we want to have productive disagreements with one another about which outcomes do more good, it’s important to make it clear whether disagreements arise from claims about value or from claims about facts.
Suppose Peter Singer and William MacAskill, two prominent effective altruist philosophers, disagree about whether option A is better than option B. If we assume that Singer and MacAskill have the same views on value, the disagreement is a factual one. By comparison, GiveWell’s analysis combines the opinions of multiple people who have different views about value, it’s not possible to tell whether one disagrees with GiveWell (supposing one does) because one differs about facts or about values. To make this plain, as noted, the key question in GiveWell’s cost-effectiveness is “how many years of doubled consumption are as morally valuable as saving the life of an under-5-year old child?” Here is a non-exhaustive list of factors two people could disagree about when answering that question, and whether that factor is a question of fact or value.
At the Happier Lives Institute, our research focuses on how much different outcomes improve happiness. While this has generally been judged subjectively in the past, we believe it is a question of fact, not of value (for a given account of happiness).
Despite long-standing doubts, happiness can be measured through population surveys and therefore we should use data from happiness surveys, rather than relying on our own subjective judgements, to determine what increases happiness. Specifically, we recommend life satisfaction (LS) scores, which are found by asking “How satisfied are you with your life nowadays?” (on a scale from 0 “not at all” to 10 “completely”) as the most suitable (although not ideal) proxy measure of happiness. The challenges of measuring happiness are explored in more detail in the sections that follow.
 Assuming we mean ‘best’ in a moral, rather than merely aesthetic, sense.
 Technically, (a) and (b) suffice only to give us a fixed-population axiology. A third component (c), specifying who the bearers of value are (i.e. present, actual, necessary or possible people) is needed to give us a variable-population axiology. Perhaps confusing, what philosophers call a ‘population axiology’ usually just specifies (b) and (c).
 Both think the value of a state of affairs is the total happiness of those who exist in that state of affairs (hedonic totalism?)