Effective altruists (EAs) want to do as much good as possible with the charitable resources available to them. If EAs want to do the most good per dollar spent—that is, if they want to maximize cost-effectiveness—they need a common currency for comparing very different interventions. GiveWell, Open Philanthropy, Founders Pledge, and many other effective altruist organizations currently have such a metric: namely, the number of “disability-adjusted life years (DALYs) averted.” A DALY is a health measure with two parts: years of life lost and years lost to disability. The former measures the extent to which a condition shortens a person’s life; the latter measures the health impact of living with a condition in terms of years of life lost. Together, these values represent the overall burden of the condition. So, averting a DALY is averting a loss—namely, the loss of a single year of life that is lived at full health.

Continue reading How to Express Improvements in Animal Welfare in DALYs-averted