This is the third of six posts I’m writing for Effective Altruism Week.

As I mentioned in previous posts, effective altruists look for the best opportunities that we can find to do the most good. So what are those?

By far the most popular causes among effective altruists are those connected to global poverty. Over a billion people currently live in extreme poverty, which is generally defined as living on less than $1.25 per day. Approximately 19,000 children die every day of preventable diseases and other poverty-related causes. This is the great humanitarian crisis of our time, and it’s within our power to help.

Most of the best global poverty charities are focused on health interventions. A lot of people have had various bright ideas about how to alleviate extreme poverty, and a lot of those bright ideas ended up not panning out for whatever reason. But saving people from preventable diseases has generally worked pretty well.

According to the best research we have so far, the interventions that work best are:

• Malaria nets. Malaria is one of the biggest killers in poor tropical and subtropical countries, especially in Africa. It’s caused by a blood parasite that’s spread by mosquito bites, so malaria infections can be prevented by sleeping under bednets treated with insecticide. The best life-saving health intervention that we know of is to distribute these nets to poor people living in malaria-affected regions. There are a number of charities working in this space, but by far the best is the Against Malaria Foundation, one of GiveWell’s most highly recommended charities. If your goal is to save human lives in the near term with the maximum possible cost-effectiveness, they’re the ones to donate to.
• Deworming. Many neglected tropical diseases, most notably schistosomiasis, are caused by parasitic worms. Among diseases caused by parasites, the death toll of schistosomiasis is second only to malaria, and children who survive it often suffer from stunted development. Schistosomiasis and similar diseases can be prevented with inexpensive deworming pills. Two of GiveWell’s top charities are focused on deworming: the Schistosomiasis Control Initiative, which directly runs deworming programs in sub-Saharan Africa, and the Deworm the World Initiative, which works primarily in India and provides technical assistance and advocacy for government-run deworming programs there.
• Micronutrient fortification. In rich countries, staple foods are routinely fortified with micronutrients; iodized salt is a good example. People in many poor countries don’t benefit from this, and end up suffering from micronutrient deficiency disorders, which are especially harmful for children’s development (for example, iodine deficiency is a leading cause of preventable intellectual disability in Africa and Southeast Asia). Micronutrient fortification is actually quite cheap if you do it at scale; as such, most of the best charities here work with national governments to set up fortification programs for entire populations. GiveWell notes the Iodine Global Network (IGN) and the Global Alliance for Improved Nutrition (GAIN) as standout organizations working specifically on salt iodization; Giving What We Can recommends Project Healthy Children, which works on a broader set of fortification programs.
• There are a few less-studied interventions that show promise; GiveWell has a list of ones that they’ve looked at. Two other GiveWell standout charities are Development Media International, which produces radio and television broadcasts to promote good health practices in the developing world, and Living Goods, which supports a network of people in sub-Saharan Africa selling health products within their own communities. The Life You Can Save also has a list of recommended charities, most of which are focused on global health.

There’s also one well-studied global poverty intervention that isn’t specifically about health: cash transfers. How do you help poor people? By giving them money. The major player in the space of unconditional cash transfers is GiveDirectly, which is also recommended by GiveWell and which I’ll be writing more about in a later post.