We feel very good about recommending that donors give to our top charities, and they’re where all GiveWell staff are – happily and confidently – giving our personal donations this year.

That said, we’re skeptical by nature, and internally, we keep thinking about and discussing the ways in which our top charities might not work out: i.e., the scenarios/circumstances in which giving to these charities doesn’t accomplish what we expect or our views change substantially in the next year about what donations to these charities accomplish.

If I were going to write the equivalent of a “dissenting opinion” for our top charities, it would be based on the issues below.

AMF: insecticide-treated net distributions

Our #1-ranked organization is the Against Malaria Foundation (AMF). Our recommendation relies on the fact that there have been numerous randomized controlled trials (RCTs, i.e., high-quality studies) tying net distributions to reductions in childhood mortality, but there’s a question of external validity for these RCTs. Is it reasonable to assume that net distributions of the type AMF carries out will have the same sort of effects they’ve had in the studies? There are a couple of reasons to question whether they will.

In our analysis of the RCTs, we found one trial where researchers conducted random spot checks to people’s houses at 5 in the morning to make sure that nets were being used. In another case, researchers, themselves, installed the nets in participants’ homes. In general, we had the impression that researchers were working hard to make sure that nets were used as intended. While AMF’s distributions (and large-scale distributions in general) involve some measures for community education and monitoring of usage, we don’t think they’re comparable to what was done in the RCTs.

For nets to be effective, people need to use them appropriately and consistently. It’s not hard to imagine someone receiving a net one day, but over time not consistently using it well.

The best available data seems to indicate that on a large scale, people use their nets relatively consistently – in line with the usage rates seen in the RCTs (which did not, themselves, reach 100% usage). But the best available data isn’t as robust as we’d like it to be, particularly when it comes to the distinction between “reported usage” and “actual usage” (our best attempts to adjust for this indicate that it is not a major issue, but we aren’t working off much information).

Another way in which large-scale net distributions could fail to live up to the small-scale studies has to do with malaria transmission dynamics. It’s possible that mosquito populations and transmission dynamics have changed in the several years since the last small-scale study was done; it’s possible that the studies were done in areas that were unusually well-suited to seeing big drops in malaria come from nets; it’s even possible that widespread use of nets could lead to increasing resistance in mosquito populations over time. We haven’t seen any strong reasons to believe that any of these things are the case; in particular, we don’t believe that data on transmission dynamics is strong enough for the small-scale studies to have picked out particularly favorable settings. But it’s a definite point of uncertainty.

One point of reassurance here: as we observed previously, the malaria control community spends a huge amount of money on distributing nets. So if one of these concerns ends up being a huge problem, finding out about it (as we hope AMF will) could be hugely beneficial in and of itself, by helping the malaria community better execute distributions and/or better allocate resources.

SCI: deworming

Our evidence review of deworming concludes that there isn’t a particularly strong case that deworming has a significant impact on individuals’ life outcomes. The evidence boils down to (a) two well-respected but far-from-ironclad research papers on the long-term effects of deworming and (b) a large degree of evidence that deworming has a consistent (but limited) impact on haemoglobin levels (which are measured to determine anemia). Our positive view of deworming stems from the fact that although there is limited evidence of quality-of-life significance, the intervention is so cheap that it is likely to be a relatively good buy and may be a great buy.

Our view of deworming is highly susceptible to change based on evidence. A single pre-registered, large-sample RCT that did not find significant impacts on development for dewormed children would significantly adjust our view about the likely impacts of deworming. Combing through the data of one of the existing papers on deworming – which we plan to do in 2012 – could easily adjust our view of the intervention. In addition, despite the fact that SCI’s evidence of impact is as strong as we’ve ever seen in a charity, we still have our doubts about it.

Given this situation, it’s not hard to picture a world in which our view shifts substantially by the end of next year.

Both organizations

Both AMF and SCI partner with governments and NGOs to implement their prorgrams. This means that neither is in complete control of their activities and they could run into problems caused by, among other things, (a) lack of funding for the components of their programs that they don’t directly fund (more on this in Holden’s recent post about charitable leverage) or (b) governments changing their minds about working with each. Note that SCI has already had one program (in Zambia) where results have been quite disappointing and data remains thin.

Difficulty in dealing with partners is a significant risk in aid, and one we’ve learned about this past year from some of the challenges VillageReach is facing in its scaleup in Mozambique.

Putting the dissents in context

The above concerns are very real, but they’re much smaller than the concerns we have for any other charity in existence.

Some seem to believe that concerns ought to be hidden from donors, to encourage them to give. This may make sense for many donors. When dealing with our own audience, we feel much better asking you to give with eyes wide open: recognize that there are no guarantees, but that the things your money can accomplish – in terms of improving others’ lives – are incredible. We think that’s more than enough reason to give without regret.