Effective altruism (EA) asks: How can we do the most good using reason and evidence? And what are concrete actions we could take? EA is partly a research project, investigating what the most pressing problems are and what the most effective solutions are to these problems. EA is also a community of people from many backgrounds and professions who seek to use their resources (time, money, and careers) to do the most good.

Many people want to do good in the world. But many of these attempts to do good are largely ineffective and do not achieve their intended goals. Some ways of doing good are much more effective. For example, some charities are 100 times more effective than others, helping 100 as many people with the same amount of resources. Differences in effectiveness are neither largely known nor considered when making decisions. Returning to the charity example, about $450 billion is donated to charity annually in the US, but most donations don't go to effective charities. By practicing effective altruism, we can achieve more good even by using the same amount of resources.

Psychological research can inform effective altruist thinking. For example, some decisions could have profound implications for the long-term future, such as whether to detonate a nuclear weapon, create a potentially dangerous new technology, and invest in pandemic preparedness. Understanding the psychology of these decisions is one step to ensuring they are made more wisely. In addition, a better understanding of human psychology might help determine the best action to take from an effective altruist perspective. For example, what makes voters elect potentially dangerous leaders, and how can we prevent it? What interventions most cost-effectively improve human psychological wellbeing? Finally, psychology research can help us spread effective altruist principles in broader society, e.g. by understanding and overcoming the psychological barriers to it.

Longtermism is the view that positively influencing the long-term future is a key moral priority of our time. An existential risk is any risk that has the potential to eliminate all of humanity or human potential. Many researchers believe that humanity is in a uniquely dangerous period in its development, characterized by unprecedented destructive capability.

If humanity does not go extinct, there could be an enormous number of future people. The principles of EA are such that all people, including future people matter, so it is a key priority for us to improve their lives and safeguard humanity against catastrophes that could prevent future people from ever existing. In other words, one of the most effective ways to do good in the world may be by mitigating existential risk.