A new research note is up on the Global Priorities Project site.
Summary of the note:
Global public health remains a top contender for the best way to improve welfare through aid. Within health interventions, it is natural to allocate marginal spending to avert the most expected DALYs (disability adjusted life-years) per dollar.
However, not all DALYs are the same and there are important differences between years of life lost (YLLs) and years lived with disability (YLDs). Not accounting for these categories separately may introduce a bias in decision-making because DALYs do not address non-health outcomes for individuals and the effects of outcomes on others. These effects are different in situations which involve primarily YLLs as opposed to YLDs. This analysis is of particular practical importance to effective altruists because two of the most promising interventions address different types of DALYS – deworming primarily averts YLDs and bed nets to prevent malaria primarily avert YLLs. This make us more inclined towards deworming as a top intervention than a naive evaluation would suggest. More sophisticated analyses incorporate terms that address many of these effects, but may still undervalue deworming relative to malaria nets.
This document is primarily written for people who already place a high weight on DALYs in identifying top public health opportunities. It does not argue for the use of DALYs, or consequentialist reasoning in identifying public health opportunities.
You can view the full article here.
This makes a lot of sense and does seem like an important distinction to make. I like the analysis as well.
Are there ways to apply some more numbers (i.e. in terms of the economic impact of YLL in middle age) where appropriate, or is that number not available? It seems like maybe applying it to those specific geographies could be helpful?
In addition, one consideration that I didn't see mentioned (but may have missed) is the economic cost of additional children. Infant mortality is a key component of having more children, and therefore there is more familial early capital spent and maternal health risk when infant mortality is higher.
I'd love to have numbers for these effects. I'm not sure whether they exist.
There is definitely a substantial economic cost to infant mortality and we weren't trying to claim otherwise. The claim was that this tends to be small in comparison to the economic cost of for example disease in children accruing the same number of DALYs.
The bottom link is broken. I believe it should point to http://globalprioritiesproject.org/2015/03/ylds-and-ylls/
Great article. Very glad to see progress on these questions. Nice work! A couple of questions seem a little underdeveloped (possibly lost to parsimony?):
1 - do YLD from schistosomiasis incur significant externalities (cognitive development, food supply and future prospects seem to be the main ones? Quite a mild condition) of the type that you bring up for the rule of thumb
2 - doesn't infant death expectation have something to do with the grief phenomenon being less strong in the developing world? Isn't this an important element of a culture in terms of accepting death etc. Doesn't it have knock on effects in terms of family planning choices and growth?
Once again, good work and thank you!
1 - Probably yes. GiveWell go into a reasonably detailed discussion of evidence for this here.
2 - Certainly yes. But I think these effects are likely to be weaker for infants than for young adults.
Very helpful as ever Owen, thanks!
Having read the Givewell page, the side effects / resistance stuff that the now replaced SCI woman in charge of evaluation was worried about are under-explored compared to what I expected of givewell (interestingly, we might be incentivising SCI to omit the routine and systematic collection and reporting of side effects and resistance - and others are not really likely to do it). This is really disappointing because I remember Toby and I being worried about this stuff back in 2010/2011.
The evidence for developmental correlates of deworming is much weaker than I had assumed knowing about the developmental correlates of under-nutrition (e.g. growing up with a hole in your brain).
Further, that evidence probably relies on the extra schooling from what they've said. I yet again revise my estimate of SCI's effectiveness downwards :( :) (depending on if I'm sad about the lower marginal effectiveness or happy about having discovered something useful!)
Woah! Hauke Hillebrand and some Harvard professors cause an extremely quick update with a facebook post to one of his first blogs on SCI effectiveness.
It seems to help HIV to the point where its effectiveness should be considered doubled (pending checks on the quality of the research).
And HIV very much is a YLD we would want to take extremely seriously, for the reasons you mentioned!
Very helpful as ever Owen, thanks!