It was a pleasure to see all major strands of the effective altruism movement gathered in one place at last week's Effective Altruism Summit.

Representatives from GiveWell, The Life You Can Save, 80,000 Hours, Giving What We Can, Effective Animal Altruism, Leverage Research, the Center for Applied Rationality, and the Machine Intelligence Research Institute either attended or gave presentations. My thanks to Leverage Research for organizing and hosting the event!

What do all these groups have in common? As Peter Singer said in his TED talk, effective altruism "combines both the heart and the head." The heart motivates us to be empathic and altruistic toward others, while the head can "make sure that what [we] do is effective and well-directed," so that altruists can do not just some good but as much good as possible.

Effective altruists (EAs) tend to:

1. Be globally altruistic: EAs care about people equally, regardless of location. Typically, the most cost-effective altruistic cause won't happen to be in one's home country.
2. Value consequences: EAs tend to value causes according to their consequences, whether those consequences are happiness, health, justice, fairness and/or other values.
3. Try to do as much good as possible: EAs don't just want to do some good; they want to do (roughly) as much good as possible. As such, they hope to devote their altruistic resources (time, money, energy, attention) to unusually cost-effective causes. (This doesn't necessarily mean that EAs think "explicit" cost effectiveness calculations are the best method for figuring out which causes are likely to do the most good.)
4. Think scientifically and quantitatively: EAs tend to be analytic, scientific, and quantitative when trying to figure out which causes actually do the most good.
5. Be willing to make significant life changes to be more effectively altruistic: As a result of their efforts to be more effective in their altruism, EAs often (1) change which charities they support financially, (2) change careers, (3) spend significant chunks of time investigating which causes are most cost-effective according to their values, or (4) make other significant life changes.

Despite these similarities, EAs are a diverse bunch, and they focus their efforts on a variety of causes.

Below are four popular focus areas of effective altruism, ordered roughly by how large and visible they appear to be at the moment. Many EAs work on several of these focus areas at once, due to uncertainty about both facts and values.

Though labels and categories have their dangers, they can also enable chunking, which has benefits for memory, learning, and communication. There are many other ways we might categorize the efforts of today's EAs; this is only one categorization.

Focus area 1: Poverty reduction

Here, "poverty reduction" is meant in a broad sense that includes (e.g.) economic benefit, better health, and better education.

Major organizations in this focus area include:

• GiveWell is home to the most rigorous research on charitable causes, especially poverty reduction and global health. Their current charity recommendations are the Against Malaria Foundation, GiveDirectly, and the Schistosomiasis Control Initiative. (Note that GiveWell also does quite a bit of "meta effective altruism"; see below.)
• Good Ventures works closely with GiveWell.
• The Life You Can Save (TLYCS), named after Peter Singer's book on effective altruism, encourages people to pledge a fraction of their income to effective charities. TLYCS currently recommends GiveWell's recommended charities and several others.
• Giving What We Can (GWWC) does some charity evaluation and also encourages people to pledge 10% of their income effective charities. GWWC currently recommends two of GiveWell's recommended charities and two others.

In addition, some well-endowed foundations seem to have "one foot" in effective poverty reduction. For example, the Bill & Melinda Gates Foundation has funded many of the most cost-effective causes in the developing world (e.g. vaccinations), although it also funds less cost-effective-seeming interventions in the developed world.

In the future, poverty reduction EAs might also focus on economic, political, or research-infrastructure changes that might achieve poverty reduction, global health, and educational improvements more indirectly, as when Chinese economic reforms lifted hundreds of millions out of poverty. Though it is generally easier to evaluate the cost-effectiveness of direct efforts than that of indirect efforts, some groups (e.g. GiveWell Labs and The Vannevar Group) are beginning to evaluate the likely cost-effectiveness of these causes.

Focus area 2: Meta effective altruism

Meta effective altruists focus less on specific causes and more on "meta" activities such as raising awareness of the importance of evidence-based altruism, helping EAs reach their potential, and doing research to help EAs decide which focus areas they should contribute to.

Organizations in this focus area include:

• 80,000 Hours highlights the importance of helping the world effectively through one's career. They also offer personal counseling to help EAs choose a career and a set of causes to support.
• Explicitly, the Center for Applied Rationality (CFAR) just trains people in rationality skills. But de facto they are especially focused on the application of rational thought to the practice of altruism, and are deeply embedded in the effective altruism community.
• Leverage Research focuses on growing and empowering the EA movement, e.g. by running Effective Altruism Summit, by organizing the THINK student group network, and by searching for "mind hacks" (like the memory palace) that can make EAs more effective.

Other people and organizations contribute to meta effective altruism, too. Paul Christiano examines effective altruism from a high level at Rational Altruist. GiveWell and others often write about the ethics and epistemology of effective altruism in addition to focusing on their chosen causes. And, of course, most EA organizations spend some resources growing the EA movement.

Focus area 3: The far future

Many EAs value future people roughly as much as currently-living people, and therefore think that nearly all potential value is found in the well-being of the astronomical numbers of people who could populate the far future (Bostrom 2003; Beckstead 2013). Future-focused EAs aim to somewhat-directly capture these "astronomical benefits" of the far future, e.g. via explicit efforts to reduce existential risk.

Organizations in this focus area include:

• The Future of Humanity Institute at Oxford University is the primary hub of research on existential risk mitigation within the effective altruism movement. (CSER may join it soon, if it gets funding.)
• The Machine Intelligence Research Institute focuses on doing the research needed for humanity to one day build Friendly AI that could make astronomical numbers of future people enormously better off. It also runs the Less Wrong group blog and forum, where much of today's EA analysis and discussion occurs.

Other groups study particular existential risks (among other things), though perhaps not explicitly from the view of effective altruism. For example, NASA has spent time identifying nearby asteroids that could be an existential threat, and many organizations (e.g. GCRI) study worst-case scenarios for climate change or nuclear warfare that might result in human extinction but are more likely to result in "merely catastrophic" damage.

Some EAs (e.g. Holden Karnofsky, Paul Christiano) have argued that even if nearly all value lies in the far future, focusing on nearer-term goals (e.g. effective poverty reduction or meta effective altruism) may be more likely to realize that value than more direct efforts.

Focus area 4: Animal suffering

Effective animal altruists are focused on reducing animal suffering in cost-effective ways. After all, animals vastly outnumber humans, and growing numbers of scientists believe that many animals consciously experience pleasure and suffering.

The only organization of this type so far (that I know of) is Effective Animal Activism, which currently recommends supporting The Humane League and Vegan Outreach.

Major inspirations for those in this focus area include Peter Singer, David Pearce, and Brian Tomasik.

Other focus areas

I could perhaps have listed "effective environmental altruism" as focus area 5. The environmental movement in general is large and well-known, but I'm not aware of many effective altruists who take environmentalism to be the most important cause for them to work on, after closely investigating the above focus areas. In contrast, the groups and people named above tend to have influenced each other, and have considered all these focus areas explicitly. For this reason, I've left "effective environmental altruism" off the list, though perhaps a popular focus on effective environmental altruism could arise in the future.

Other focus areas could later come to prominence, too.

Working together

I was pleased to see the EAs from different strands of the EA movement cooperating and learning from each other at the Effective Altruism Summit. Cooperation is crucial for growing the EA movement, so I hope that even if it’s not always easy, EAs will "go out of their way" to cooperate and work together, no matter which focus areas they’re sympathetic to.