No. 1 QALY/year is how good a normal life is. But a life could be better than that, and a life could be more bad than a good life is good. If I’d be willing to give up 10 years of normal life to avert 1 year on a factory farm, then that means a year on a factory farm is worth −10 QALYs.
How does the estimate go above 1 QALY/year? Isn’t that the maximum possible?
No. 1 QALY/year is how good a normal life is. But a life could be better than that, and a life could be more bad than a good life is good. If I’d be willing to give up 10 years of normal life to avert 1 year on a factory farm, then that means a year on a factory farm is worth −10 QALYs.