Dumb question time. Quality adjusted life years and disability adjusted life years -- I see these a lot in the literature. What is the difference between the two and which is the best measure from a utilitarian perspective?

They mean the same thing. DALY was made just for medical stuff, and QALY was made for general utilitarian stuff later on, so that it doesn't imply that the cause of unhappiness is a physical disability. It's likely to be poverty, for example.

Hi all,
The difference is not always clear, but:
1. It seems like QALYs were described 20 years before DALYs (http://heapol.oxfordjournals.org/content/21/5/402.short)
2. It seems like QALYs describe years gained whereas DALYs describe years lost to a disease. (http://www.qalibra.eu/tool/support/page8.cfm)

As RyanCarey indicates, 1 QALY is one year of life at full health (or equivalent) gained, whereas 1 DALY is one year of life at full health (or equivalent) lost. So we want to gain QALYs and avert DALYs.

I think that QALYs are the best measure from a utilitarian perspective, as the use of DALYs seems to always accompany the assumption that people live to 80 (and thus overemphasises the badness of people dying early in developing countries). I don't know the details though; PM Will Crouch (he's on Felicifa) if you want to know more.

LadyMorgana wrote:1 QALY is one year of life at full health (or equivalent) gained.

What would an equivalent be? Also, you can be at full health and completely miserable at the same time, or inversely, not at full health but happy and living. Is there any remotely reliable empirical metric for the actual hedonistic value of a life-year (human or otherwise)?

What would an equivalent be? Also, you can be at full health and completely miserable at the same time, or inversely, not at full health but happy and living.

It's the average happipness of a healthy person for a year. If you're half as happy as average for two years, that's one QALY. Similarly, if you're twice as happy for six months, that's half a QALY.

Is there any remotely reliable empirical metric for the actual hedonistic value of a life-year (human or otherwise)?

Yes. Surveys on how happy people are are generally accepted to be remotely reliable.