[Economists] have developed a metric called the quality-adjusted life year, or QALY (pronounced "kwalee"), in order to help make decisions about how to prioritize among different health programs [one year of life in good health].
p. 40
The difficulty of comparing different sorts of altruistic activity is [...] ultimately due to a lack of knowledge about what will happen as a result of that activity, or a lack of knowledge about how different activities translate into improvements to people's lives. It's not that different sorts of benefits are in principle incomparable.
Within economics and decision theory the standard way to [compare speculative actions] is to look at an action's expected value [monetary gain or loss multiplied by its probability].
p. 82
Public health experts use the concept of a “micromort” to compare risks, where one micromort equals a one-in-a-million chance of dying, equivalent to thirty minutes of expected life lost if you're aged twenty, or fifteen minutes of expected life lost if you're aged fifty. [...] Based on reported cases of deaths [...], one ecstazy session (two tablets) is only about one micromort, whereas going scuba diving is five micromorts and going skydiving is nine micromorts. Flying in a space shuttle is seventeen thousand micromorts, or a 1.7 percent chance of dying, which is about as dangerous as attempting to climb Mount Everest beyond base camp, at thirteen thousand micromorts, or a 1,3 percent chance of dying.
pp. 85-86
An economist might say that, for you, the expected value of voting is only one in sixty million times $1,000, which equals 0.0016 cents. With such a low expected value, it's clearly not worth it to vote.
But this line of reasoning assumes that the value of voting is only the value to you. Instead, we should think about the total benefit of the better party in power. Let's keep this hypothetical $1,000 figure of the benefit per person of the better party being in power. If so, the total benefit to all Americans is $1,000 multiplied by the US population of 314 million, so $314 billion. [...] That's the sense in which voting is like donating thousands of dollars to (developed world) charities. For all but the ultrarich, that's a much better useof time than you could get, for example, by working the hour it takes you to vote and donating your earnings.
p. 95
Climate change is another issue where the concept of expected value proves useful.
One of the most damning examples of low-quality evidence concerns microcredit (that is, lending small amounts of money to the very poor, a form of microfinance most famously associated with Muhammad Yunnus and the Grameen Bank).
A review commissioned by the Fairtrade Foundation itself concluded that “there is limited evidence of the impact on workers of participation in Fairtrade.”
p. 136
The same food can sometimes have a higher carbon footprint if it's locally grown than if it's imported: one study found that the carbon footprint from locally grown tomatoes in northern Europe was five times as great as the carbon footprint from tomatoes grown in Spain, because the emissions generated by heating and lighting greenhouses dwarfed the emissions generated by transportation.
pp. 138-140
Cool Earth does not buy rain forest directly; instead, it provides economic assistance to local communities, helping the people who inhabit the rain forests establish more profitable ventures than selling trees. [...] The work Cool Earth does therefore incidentally improves the lives of those living in the rain forest while working to prevent climate change.
Using this [...] the average American adult would have to spend $105 per year to offset all their carbon emissions. This is significant, but to most people it's considerably less than it would cost to make large changes in lifestyle, such as not flying.
Though effective altruism aims to take a scientific approach to doing good, it's not exactly physics: there is plenty of room for differences of opinion. This doesn't, however, make thinking rigorously about which cause one chooses to focus on any less important.pp 185-195
On the framework I propose, you can compare causes by assessing them on how well they do on each of the following three dimensions: scale, neglectedness, tractability.
If we're thinking about contributions of time rather than just money, then there is a fourth dimension: personal fit.
Let's look at some high-priority causes.
Scale: From fairly large to extrbely large, depending on value judgbents.
Neglectedness: Fairly neglected.