1) I happen to know quite a bit about the rationale behind the GBD 2010 method as I was involved near the end of the process. It is designed to avoid talking about evaluative questions of the quality or value of life and to only talk about the descriptive question of the level of health—something that doctors are meant to plausibly have more expertise on. This change avoids certain critiques of the method, but I and many other philosophers and economists think that it is quite a bit worse overall and possibly incoherent. At least for effective altruism, we only care about health states in terms of answering normative questions of which option to choose and here we care about the evaluative measures of quality. Notably these come apart from the descriptive ones in cases like intellectual disability and infertility. People don’t rate people with these conditions as much less healthy, but they do agree that their lives are made quite a bit worse. When things come apart like this, it is the badness in their lives that should matter. I was more sanguine about this before I read your article as I’d heard there was at least a strong correlation between these new numbers and the old ones, but your quantitative correlation chart shows that it is not that strong. I’d thus use one of the earlier approaches, or one of the many QALY type approaches that have been done in parallel with these DALY ones.
2) Regarding scepticism about the weightings, it is not like there is any other sensible option but to use them (well, one version or another of them). Using one’s own intuition about how bad two health states are is obviously worse than at least one of the current aggregate measures, as is considering all ill-health to be equally bad. Rejecting these aggregate health quality weights means using some other form of health quality weight which will be worse. It is OK to think that these quality weight numbers introduce another level of noise into cost-effectiveness—they do! -- and we don’t have any better options but to use them. Also, the noise introduced is not all that much compared to the signal (I’d say it introduces less than a factor of 2, when the data shows many things separated by factors of 100 or more), so the results can still be used for many purposes.
Thanks for this great summary Jeff!
Here are a couple of comments:
1) I happen to know quite a bit about the rationale behind the GBD 2010 method as I was involved near the end of the process. It is designed to avoid talking about evaluative questions of the quality or value of life and to only talk about the descriptive question of the level of health—something that doctors are meant to plausibly have more expertise on. This change avoids certain critiques of the method, but I and many other philosophers and economists think that it is quite a bit worse overall and possibly incoherent. At least for effective altruism, we only care about health states in terms of answering normative questions of which option to choose and here we care about the evaluative measures of quality. Notably these come apart from the descriptive ones in cases like intellectual disability and infertility. People don’t rate people with these conditions as much less healthy, but they do agree that their lives are made quite a bit worse. When things come apart like this, it is the badness in their lives that should matter. I was more sanguine about this before I read your article as I’d heard there was at least a strong correlation between these new numbers and the old ones, but your quantitative correlation chart shows that it is not that strong. I’d thus use one of the earlier approaches, or one of the many QALY type approaches that have been done in parallel with these DALY ones.
2) Regarding scepticism about the weightings, it is not like there is any other sensible option but to use them (well, one version or another of them). Using one’s own intuition about how bad two health states are is obviously worse than at least one of the current aggregate measures, as is considering all ill-health to be equally bad. Rejecting these aggregate health quality weights means using some other form of health quality weight which will be worse. It is OK to think that these quality weight numbers introduce another level of noise into cost-effectiveness—they do! -- and we don’t have any better options but to use them. Also, the noise introduced is not all that much compared to the signal (I’d say it introduces less than a factor of 2, when the data shows many things separated by factors of 100 or more), so the results can still be used for many purposes.
I agree with this and think it’s important enough to highlight.