Changes in estimated cost-effectiveness of AMF
- A donor recently emailed us asking about the changes in our cost-effectiveness estimates for AMF. The donor pointed out that our estimate had changed and whether this was the result of changes in conditions on the ground that changed the actual cost-effectiveness of AMF, or from the appearance of new evidence that just changed our estimate. This is a question we think a number of people might have, so we wanted to share our response:The changes in our cost-effectiveness figures for AMF are due entirely to revisions in our calculation, rather than either (a) changing conditions on the ground; or (b) evidence that was not available at the time of our initial review becoming available. The shift from an estimate of roughly $1,600 per life saved to roughly $2,300 per life saved is the result of a single change to our calculation, described in the penultimate section of this blog post: http://blog.givewell.org/2012/10/18/revisiting-the-case-for-insecticide-treated-nets-itns/ (see "All-cause childhood mortality has declined; what does this mean for ITN distribution?"). Essentially, the studies we use to estimate the mortality benefits of bednets were conducted in the mid-1990s; since then, child mortality has declined by about 30%. The only change to our estimate was switching from assuming that bednets saved a certain absolute proportion of children covered to assuming that bednets avert a certain proportion of child mortality.We explain this in a little more depth in the current version of our intervention report on bednet distributions:
We include a simple adjustment to account for the fact that child mortality rates are lower today than they were at the time of the studies on ITNs.76 This adjustment assumes that ITNs avert the same proportion of under-5 deaths that they averted at the time of the studies. This could be incorrect.
Best,Alexander--Alexander BergerResearch Analyst
- The deaths averted by ITNs may be the same deaths that could be averted by, for example, vitamin A supplementation (as noted above, many of the deaths averted by ITNs are not specifically attributable to malaria). So perhaps other improvements in general health are independently averting all the deaths that ITNs could avert in their absence; under this model it’s possible that ITNs don’t avert any deaths at all.
- On the flipside, there may be increasing returns to improved general health: perhaps there are children who previously (at the time of the studies) would have been in such poor health that they would have died even with ITNs, but now can have their deaths averted by ITNs.