[Part of an occasional series in which I explain the evidence for various EA top charities. You can get all of this information on GiveWell’s website, but I’m more fun and swear more. I want this post to be accurate and will correct it for factual mistakes. If you are reading it more than about a year in the future, it is probably not currently accurate.]

Many people believe that deworming is a public health intervention. It’s not. It is a development intervention cunningly disguised as a public health intervention. In most public health interventions, the benefit comes from people being less sick and less dead, and on that metric deworming doesn’t actually do particularly well. What gets people excited about deworming as an intervention is its effect on economic and educational indicators.

If you are a serious charity nerd, you may have heard of something called the worm wars, the best-named drama since the feminist sex wars. If you’re interested in getting into the serious nitty-gritty of the worm wars, that post I just linked will have you covered for days. For those of you who don’t have an endless appetite for epidemiologist-economist drama (I can’t imagine why not), I will summarize. One of the big knock-down studies in favor of deworming as an intervention argued that deworming improved rate of school absenteeism, although not test scores. However, it had significant errors and failed to replicate, and now everyone is arguing with each other about whether that means deworming is still a best-buy intervention.

You might think it’s super-weird that GiveWell has continued to support an intervention that failed to replicate! However, GiveWell’s recommendation isn’t actually based on the thing everyone’s arguing about: it’s based on a followup to the same study that showed that the treatment group earned more money and were more likely to be employed. However, reducing school absenteeism is one plausible way that treating worms might increase income; if deworming doesn’t actually reduce school absenteeism, there is a giant glaring red flag labelled WE DON’T HAVE A PLAUSIBLE MECHANISM FOR WHY THIS WORKS.

The reason GiveWell supports deworming is that deworming is really super fucking cheap. Like, amazingly cheap. It costs about $1.25 to deworm a child; because the Schistosomiasis Control Initiative gets drugs donated and in-kind donations from governments, fifty cents donated provides a treatment to one child. Deworming is so cheap that deworming programs usually work by giving everyone in the school deworming pills, because that’s actually cheaper than testing kids for worms so that it only goes to the actually sick kids.

So even if deworming only has a small chance of having a big benefit, deworming is cheap enough that it’s worth it.

The Schistosomiasis Control Initiative has not allocated enough resources to keeping track of its finances, which leads to some embarrassing mistakes, such as having misplaced a $333,000 grant from GiveWell for nine months until GiveWell pointed it out to them. They also aren’t super-transparent with GiveWell staff. The Deworm the World Initiative, GiveWell’s other top charity that deals with deworming, does not have this organizational competence issue, but may not have a lot of room for more funding, because it has a parent organization that may fill its funding gaps. (Note that the parent organization, Evidence Action, is pretty cool, and depending on your values you may find the risk of your donation to Deworm the World actually being a donation to Evidence Action pretty uncompelling.) Honestly, which of those charities to donate to seems like a judgment call to me.

Reasons to donate to deworming:

  • You like taking risks with your donations and don’t like AI.
  • You want to donate to a development charity.
  • You wish to encourage epidemiologists and economists to have more extremely entertaining fights.