Glossary
Common terms in effective altruism explained in plain language.
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80,000 Hours
80,000 Hours is an international nonprofit that provides free research and support to help talented people move into careers that tackle the world’s most pressing problems. They offer a career guide, in-depth research articles and podcasts, a job board, and career calls.
A
AI Safety
AI safety is the field of study or practice focused on ensuring that artificial intelligence systems are designed and deployed in ways that are safe and beneficial to humanity; commonly via governance, technical research or fieldbuilding.
Altruism
Altruism is the principle or practice of concern for the welfare of others.
Animal Charity Evaluators (ACE)
Animal Charity Evaluators (ACE) is an international organisation that conducts charity evaluations to identify the organisations that will likely make the most significant difference for animals. They publish a list of recommended charities to promote organisations that can do the most good for animals with additional donations. They aim to be transparent about their evaluation methods and processes and actively improve them each year.
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Biosecurity
Biosecurity covers the procedures, practices and other measures used to manage risks from biological agents (e.g. viruses, bacteria) or their products (e.g. toxins). For example, preventing a pandemic, which can be caused by human engineered pathogens.
C
Cause X
Cause X is a currently unknown cause area currently neglected by the effective altruism community, typically due to some form of moral blindness or fundamental oversight, yet more important than all the causes currently prioritized by it.
Centre for Effective Altruism (CEA)
The Centre for Effective Altruism (CEA) is a nonprofit working globally to promote the principles of effective altruism and support and grow the effective altruism community.
Consequentialism
Consequentialism is the ethical view that the rightness of an action depends solely on its outcomes. Variants differ on what outcomes matter; for instance, utilitarianism focuses on maximising well-being, while pluralistic consequentialism includes multiple values beyond well-being. For example, breaking a promise might be morally justified if doing so prevents significant harm to others.
Counterfactual impact
Counterfactual impact is the difference between what actually happened because of an action and what would have happened without it. For example, if you donate to fund a surgery and it goes ahead—but someone else would have donated if you hadn’t—the counterfactual impact of your donation is low. Accounting for this can make results seem less impressive, but it gives a more accurate picture of real impact.
Cost-Effectiveness Analysis (CEA)
Cost-effectiveness analysis (CEA) is a form of economic analysis that compares the relative costs and outcomes (effects) of different courses of action. The outcomes are not expressed in monetary value. This analysis is often used in health interventions, where the outcome is expressed in, for example, QALYs.
Cause Prioritisation
Cause priorisitisation is the process of systematically comparing world problems or charitable causes to allocate donations or career effort where they can achieve the greatest good. Many people follow their interests when deciding where to direct their efforts; cause prioritisation takes a different approach (after which personal interest of fit can still play a role). By applying the Importance, Tractability, Neglect (ITN) framework, individuals and organisations identify issues that matter most, are solvable and are less crowded already, thereby maximising their positive impact.
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Deontology
Deontology is the view that certain actions are morally required or forbidden based on rules or duties, regardless of their outcomes. It emphasises principles like justice, rights, and obligations, often rejecting the idea that good consequences can justify morally wrongful acts. For example, it would forbid lying to avoid a minor harm, since it violates a moral rule.
Disability Adjusted Life-Year (DALY)
"The DALY (Disability-Adjusted Life Year) measures disease burden by combining years lost to premature death (YLL) and years lived with disability (YLD), weighted by severity: DALY = YLL + (YLD × disability weight). It enables comparison across conditions and guides global health priorities. For example, a child dying of malaria contributes many DALYs through lost life years, while someone with chronic depression contributes DALYs through reduced quality of life."
Doneer Effectief (Donate Effectively)
Doneer Effectief is a Dutch nonprofit that helps Dutch and Belgian citizens support charities that have been evaluated as highly effective. Their selection of these top charities is based on evaluations by independent, scientific research organisations. They have a user-friendly platform, facilitate campaigns (e.g. birthdays or marathons), give donation advice via their helpdesk or via large donor advising, engage in public media and provide resources for ambassadors.
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EA Forum
The Effective Altruism Forum is a platform run by the Centre for Effective Altruism to facilitate discussions relevant to effective altruism and coordinate related projects. New posts and quick takes are published daily. Sign up for their weekly digest here. The forum also contains an overview of global EA groups and members, a wiki, the EA handbook and a forum podcast.
EA Global/EAGx
EA Global (EAG) and EAGx are conferences for both established and newer members of the effective altruism (EA) community. Each event typically runs for 2–3 days and includes talks, workshops, discussions, and extensive opportunities to connect—such as one-on-one meetings arranged through an app. Attendance ranges from a few hundred to over a thousand people. EAG events are organised by the Centre for Effective Altruism and generally have a higher application threshold than EAGx (which shouldn't keep you from applying!).
Earning to give
Earning to give is the pursuit of a lucrative career with the purpose of donating a significant portion of the earnings to cost-effective organisations.
Effective altruism (EA)
Effective altruism is a philosophy, a research field and a global community focused on using evidence and reason to do the most good. It involves identifying the world’s most pressing problems and finding high-impact ways to address them. Core principles include treating all lives as equally valuable, prioritising effectiveness, remaining open to new evidence and unusual ideas, and collaborating with integrity. This approach guides decisions about donations, careers, and policies to maximise positive impact across current and future generations.
Existential Risk (X-risk)
Existential Risk (or X-risk) is the risk of an event that could either cause human extinction or permanently and severely limit humanity’s long-term potential.
Expected value
Expected value is the anticipated value of an action, calculated by multiplying the value of each possible outcome by its probability of occurrence and then summing these products.
G
GiveWell
GiveWell is an international nonprofit dedicated to finding outstanding giving opportunities and publishing the full details of their rigorous analysis to help donors decide where to give. They recommend a list of top charities to donors and provide a Giving Funds. They focus on global health & development.
Giving What We Can (GWWC)
Giving What We Can (GWWC) is an international organisation dedicated to inspiring and supporting people to give more, and give more effectively. GWWC promotes donation pledges. The most prominent is The 10% Pledge: a commitment to donate at least 10% of one's income in the way one thinks will be most effective. GWWC also aims to support its members, to help them connect with and support each other, and to build effective altruism, effective giving, and various related cause areas.
Global Catastrophic Risk (GCR)
Global Catastrophic Risk (GCR) is a hypothetical future event that could damage human well-being on a global scale.
Global Priorities Research
Global Priorities Research is research that attempts to determine how we can do the most good with our limited resources. This field draws upon themes of economics, philosophy and psychology. GPR can involve directly identifying and comparing different causes, as well as broader ""foundational"" or macrostrategic work that informs cause prioritisation more indirectly—for example, research on the Fermi paradox or the hinge of history hypothesis.
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Hits-based giving
Hits-based giving is a philanthropic strategy that maximises expected value by embracing high-risk, high-reward opportunities, accepting frequent failures offset by rare transformative successes. It treats giving as a hits business akin to venture capital, funding neglected, counterintuitive, low-evidence ideas with potential for outsized impact, guided by importance, neglectedness and tractability. Decision-making is streamlined, deeply informed and transparent about uncertainty, foregoing deference to consensus and prioritising occasional “hits” over consistent modest returns.
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ITN framework
The ITN framework helps identify high-impact causes by assessing three factors: 1. Importance (how big and severe the problem is), 2. Tractability (how solvable it is), and 3. Neglectedness (how few resources it gets). It’s used to compare very different issues—like global health vs. AI safety—and guide where resources can do the most good. For example, reducing lead exposure in LMICs scores high on all three, making it a strong candidate for impact-focused work. ITN complements cost-effectiveness analysis in prioritising efforts.
Impact assessment
Impact assessment is a structured process for evaluating the impact of an intervention. Impact assessments can focus on an intervention's expected impact (ex-ante or prospective impact assessment) or on its actual impact (ex-post or retrospective impact assessment). Impact assessment is sometimes contrasted with impact evaluation, which is understood to be broader in scope and includes impacts not considered in standard impact assessments.
Impact evaluation
Impact evaluation is the process of assessing the changes that can be attributed to a particular intervention or project.
Impartiality
Impartiality is the motivation to choose the resources to devote to altruism, to strive to help those who need it the most, without giving more weight to those who are similar to us or live near us in space or time. (Less confidently, this often means focusing on people in developing countries, animals, and future generations.) It's one of the core principles of effective altruism.
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Longtermism
Longtermism is the view that positively influencing the long-term future is a key moral priority of our time.
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Moral uncertainty
Moral uncertainty is when we are not sure which moral theory, such as utilitarianism, deontology or virtue ethics, is correct yet must still act. It also refers to the study of how to choose when theories conflict. Whether deciding how to weigh animal welfare against human interests, duties to distant people or the ethics of bringing new lives into existence, we handle uncertainty by assigning confidence to each theory and following the choice with the highest overall support.
Moral circle expansion
Moral circle expansion is the attempt to expand the perceived boundaries of the category of moral patients. It has been proposed as a priority cause area and as a heuristic for discovering cause X.
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Quality-Adjusted Life Year (QALY)
The QALY (Quality-Adjusted Life Year) measures health benefit by combining years of life gained and the quality of those years, scaled from 0 (death) to 1 (full health): QALY = years of life × quality of life weight. It enables comparison across conditions and guides health spending. For example, extending life by 5 years at 0.6 quality yields 3 QALYs.
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Rationality
Rationality means deliberately thinking clearly to find the truth, deal with uncertainty and reach your goals. It’s about understanding how your mind works, spotting biases and choosing wisely even when things are tough. Practising rationality helps you make better decisions over time.
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S-risk
S-risks (also called suffering risks or risks of astronomical suffering) are risks of events that bring about suffering in cosmically significant amounts, compared to what future suffering is expected.
Scope Insensitivity
Scope insensitivity is the tendency to undervalue saving larger numbers of lives or resources because large quantities often feel the same, even when the actual differences are vast.
Scout mindset
Scout mindset is the motivation to see things as they are, not as you wish they were"".The scout mindset emphasises curiosity, unbiased truth-seeking, and facing reality, even if that reality is unexpected. This is contrasted with a ""soldier mindset"", which is a natural tendency to use motivated reasoning to defend one's existing beliefs instead of being open to changing them. The term 'scout mindset' is pitched and described by Julia Galef in the book 'Scout Mindset'.
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The 10% Pledge
The 10% Pledge is a global public commitment to give at least 10% of income to the organisations you believe can most effectively use it to improve the lives of others. It's one of the key initiatives of Giving What We Can.
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Utilitarianism
Utilitarianism is the family of moral theories according to which the rightness of actions is determined solely by the sum total of well-being they produce. It's a common misconception that EA equals utilitarianism or that most people within the community are utilitarians.
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Virtue ethics
Virtue ethics holds that morality depends on an agent’s character rather than specific actions or consequences. Rooted in Aristotle’s thought, it defines virtues as balanced traits like courage, and sees the right action as what a fully virtuous person would do. For example, telling the truth out of honesty (rather than obligation or outcome) reflects moral character.
W
Wild Animal Suffering
Wild animal welfare is the welfare of non-human animals under natural conditions, and the study of interventions aimed at improving the welfare of these animals.