Doing Good Better: Effective Altruism and a Radical New Way to Make a Difference

by William MacAskill

Many people want their lives to make a difference and, if you’re reading this book, you’re probably one of them. As Trevor Field’s story illustrates, however, good intentions can all too easily lead to bad outcomes. The challenge for us is this: how can we ensure that, when we try to help others, we do so as effectively as possible? How can we ensure that we avoid inadvertently causing harm and have the greatest positive impact we can? This book tries to help answer these questions. I believe that by combining the heart and the head – by applying data and reason to altruistic acts – we can turn our good intentions into astonishingly good outcomes. To illustrate, let’s look at a story with a very different ending from the one you just read.

Over and over again, Kremer found that seemingly obvious programmes to improve education just weren’t working. But he persisted. He refused to believe there was simply no way to improve the education of children in Kenya. At that point a friend at the World Bank suggested he test deworming. Few people in developed countries know about intestinal worms: parasitic infections that affect more than a billion people worldwide. They aren’t as dramatic as AIDS or cancer or malaria because they don’t kill nearly as many people as those other conditions. But they do make children sick, and can be cured for pennies: off-patent drugs, developed in the fifties, can be distributed through schools and administered by teachers, and will cure children of intestinal worms for a year. Kremer did an experiment to see whether treating children for these intestinal worms had an impact on education. The results were striking. ‘We didn’t expect deworming to be as effective as it was,’ Kremer told me. ‘It turned out to be one of the most cost-effective ways of increasing school participation.’ Absenteeism is a chronic problem in schools in Kenya, and deworming reduced it by 25%. In fact, every child treated spent an extra two weeks in school, and every $100 spent on the programme provided a total of ten years of additional school attendance among all students. Enabling a child to spend an extra day in school therefore cost just 5¢. It wasn’t merely that deworming children ‘worked’ at getting chil...

independent charity evaluator GiveWell

They were willing to revise their beliefs about what worked in light of the evidence they received and then go out and do what the evidence suggested they should. In contrast with the PlayPump, the most effective programme turned out to be remarkably boring: Grace Hollister, now the director of Deworm the World Initiative, told me that, ‘deworming is probably the least sexy development programme there is’. But by focusing on what was effective rather than what was emotionally appealing, they produced outstanding results, significantly improving the lives of millions. Kremer and Glennerster exemplify a way of thinking I call effective altruism.

Effective altruism is about asking ‘How can I make the biggest difference I can?’ and using evidence and careful reasoning to try to find an answer. It takes a scientific approach to doing good. Just as science consists of the honest and impartial attempt to work out what’s true, and a commitment to believe the truth whatever that turns out to be, effective altruism consists of the honest and impartial attempt to work out what’s best for the world, and a commitment to do what’s best, whatever that turns out to be.

Around the same time, two New York hedge-fund analysts, Holden Karnofsky and Elie Hassenfeld, quit their jobs to start GiveWell, an organisation that conducts extraordinarily in-depth research to calculate which charities do the most good with every dollar they receive.

Moreover, because of that economic progress, we live at a time in which we have the technology easily to gather information about people thousands of miles away, the ability to significantly influence their lives, and the scientific knowledge to work out what the most effective ways of helping are. For these reasons, few people who have ever existed have had so much power to help others as we have today. Sometimes we look at the size of the problems in the world and think, ‘Anything I do would be just a drop in the bucket. So why bother?’ But, in light of the research shown in these graphs, that reasoning doesn’t make any sense. It’s the size of the drop that matters, not the size of the bucket, and, if we choose, we can create an enormous splash. We’ve already seen that we have the opportunity to provide a benefit for others that is one hundred times greater than the benefit we could provide for ourselves. That we can’t solve all the problems in the world doesn’t alter in any way the fact that, if we choose, we can transform the lives of thousands of people.

‘There are well known and striking donor success stories, like the elimination of smallpox, the near-eradication of river blindness and Guinea worm, the spread of oral rehydration therapy for treating infant diarrheal diseases, DDT campaigns against malarial mosquitoes (although later halted for environmental reasons), and the success of WHO vaccination programmes against measles and other childhood diseases.’

Distributions that look like this are called fat-tailed distributions. (You might have heard of the ‘80/20’ rule: that 80% of the value of an entire set of activities can be achieved by performing the best 20% of those activities. That rule describes a fat-tailed distribution.) Fat-tailed distributions are interesting because they’re marked by extreme events.

I’m using this example because it illustrates why, if we want to have an impact, we should donate to less widely publicised disasters rather than to the ones that make the news. For example, in 2008 an earthquake hit Sichuan, China. You probably haven’t heard of it: I hadn’t before I started writing this book. This earthquake struck fifty miles north-west of Chengdu, right in the centre of China. It killed 87,000 people: five times as many as the Japanese earthquake, and half as many as the Haitian earthquake. Yet it raised only $500 million in international aid – one tenth that of Haiti or Japan. For some reason, it wasn’t as widely publicised as these other earthquakes, so it received less funding. Because it received so much less, donations would have probably made a bigger impact. The law of diminishing returns also explains why, in general, it makes less sense to donate to disaster relief than it does to donate to the best charities that fight poverty. Every day people die from easily preventable diseases like AIDS, malaria, or tuberculosis. This is a disaster far beyond that of Haiti, or Tōhoku, or Sichuan. Every day over 18,000 children – more than the number of people who perished in Tōhoku – die from preventable causes. For every death the Japanese earthquake caused, aid organisations received $330,000 in donations. In contrast, for every person that dies from poverty-related causes worldwide, only $15,000 on average is spent in foreign aid and philanthropy. Partl...

Suppose, for example, that I see a woman collapse on the ground. She’s had a heart attack. There’s no one else around, so I run up to her and start performing CPR. Suppose I’ve never performed CPR before, but I manage to restart the woman’s heart. She recovers, but as a result of the poor quality CPR, is left with a disability. Even so it’s clear that I have done a great thing. Now suppose there had been a paramedic around when the woman collapsed. This paramedic would have surely restarted her heart without causing injury, but, while I was running toward the woman, I pushed the paramedic out of the way and started performing CPR myself. In this case, I still saved her life, but if I hadn’t, the paramedic would have been able to do the same thing without causing damage. In this case, how should I feel about my actions? Am I a hero? After all, I ‘saved a life’! Of course I’m not a hero. The good I do is not a matter of the direct benefits I cause. Rather, it is the difference I make. Even though I technically saved this woman’s life, I actually did harm overall. Looking at what would have happened otherwise is a fundamental piece of scientific reasoning, referred to as ‘assessing the counterfactual’. But the mistake of neglecting the counterfactual is rife within the world of altruism, and this mistake can have terrible consequences.

I suspect the apparent effectiveness of Scared Straight can be explained by a phenomenon called regression to the mean. If you play a truly excellent round of golf one day, you’ll probably play worse the next time you play because that excellent round was statistically unlikely and you should expect to see a more typical performance the next time. Similarly, people who are undergoing a bout of particularly severe depression will on average be happier three months later, because they are likely closer to their average level of happiness. And, similarly, if you select a group of juveniles to go through a reform programme because they’ve committed an unusually high number of misdemeanours in a given time period, they’re likely to exhibit something closer to typical behaviour in the following months.

Earning to give means exactly what it sounds like: rather than trying to maximise the good you do directly via your job, you instead try to increase your earnings so you can donate more, improving people’s lives through your giving rather than your day-to-day work. Most people don’t consider this option when choosing a career that ‘makes a difference’. But time and money are usually interchangeable – money can pay for people’s time, and your time can be used to earn money – so there’s no reason to assume the best careers are only those that benefit people directly through the work itself. If we’re serious about doing good, earning to give is a path we should consider. Let’s look at Greg Lewis’s options. If he worked as a doctor in a rich country and didn’t donate a portion of his income, he would do an amount of good equivalent to saving two lives over the course of his career. If he went to work as a doctor in a very poor country, he would do an amount of good equivalent to saving four lives every year, or 140 lives over a thirty-five year career. But how many lives could he save if he stayed home and donated his earnings?

It’s worth reflecting on this. In 2007 Louis Theroux, a British documentary filmmaker, released a documentary called Under the Knife in which he explored the world of cosmetic surgery in Beverly Hills. In the culmination of the show, he accused the cosmetic surgeon he’d been interviewing of wasting his talent and skills to make wannabe movie stars more attractive, rather than saving lives. What we’ve seen so far shows that Louis Theroux’s sentiment, while understandable, is misplaced. It’s the cosmetic surgeon’s decision about how to spend his money that really matters. Earning to give seems to be an enormously powerful way of doing good. It exploits the fact that even typical workers in developed countries are among the top income earners in the world, and that there are some charities that do huge amounts to help the world’s poorest people for relatively little money. Moreover, unlike the conventional ‘ethical’ careers guidance, earning to give is a path that’s open to everyone.

Maximising expected value is generally regarded as the best strategy for making decisions when you know the value and the probability of each option. It’s the strategy used by economists, statisticians, poker players, risk management experts and pretty much anyone else who regularly needs to deal with uncertain outcomes. To see why, suppose that I offer you the same bet over and over again. In the long run, you’re almost guaranteed to make more money if you accept my bets than if you don’t: in fact, on average you’ll make $0.50 for every bet that you take.

To see how useful the idea of expected value is, let’s consider a morbid but important application: assessing the risk of death from different activities. Smoking, riding a motorbike, scuba diving, taking ecstasy, eating peanut butter: all these things increase your risk of death. How much should you worry about each of them? Public health experts use the concept of a ‘micromort’ to compare the risks, where one micromort equals a one-in-a-million chance of dying, equivalent to thirty minutes of expected life lost if you’re aged twenty, or fifteen minutes of expected life lost if you’re aged fifty. By comparing different activities in terms of micromorts, we can easily assess their relative dangers. The results can be surprising. Based on reported cases of deaths from these activities, one ecstasy session (two tablets) is only about one micromort, whereas going scuba diving is five micromorts and going skydiving is nine micromorts. Flying in a space shuttle is 17,000 micromorts, or a 1.7% chance of dying, which is about as dangerous as attempting to climb Mount Everest beyond base camp, at 13,000 micromorts, or a 1.3% chance of dying.

Consider ethical consumption, like switching to Fairtrade coffee, or reducing how much meat you buy. Suppose someone stops buying chicken breasts, instead choosing vegetarian options, in order to reduce the amount of animal suffering on factory farms. Does that person make a difference? You might think not. If one person decides against buying chicken breast one day but the rest of the meat-eaters on the planet continue to buy chicken, how could that possibly affect how many chickens are killed for human consumption? When a supermarket decides how much chicken to buy, they don’t care that one fewer breast was purchased on a given day. However, if thousands or millions of people stopped buying chicken breasts, the number of chickens raised for food would decrease – supply would fall to meet demand. We’re then left with a paradox: individuals alone can’t make a difference; millions of them acting together can; but the action of millions is simply the combined actions of many individuals. Moreover, an iron law of economics is that, in a well-functioning market, if demand for a product decreases, the quantity of the product that’s supplied decreases. How, then, can we reconcile these thoughts? The answer lies with expected value. If you decline to buy some chicken breast then most of the time you’ll make no difference: the supermarket will buy the same amount of chicken in the future. Sometimes, however, you will make a difference. Occasionally the meat buyer will assess chick...

In cases where people seem to neglect the risks of worst-case outcomes, helping to prevent these outcomes might be a particularly effective altruistic activity. This is what the Skoll Global Threats Fund focuses on, trying to reduce the chances of global catastrophes arising from climate change, pandemics, and the proliferation of nuclear weapons. The charity evaluator GiveWell is currently investigating these sorts of activities in an attempt to work out how effective donations in these areas can be.

In this book so far, I’ve introduced the key questions to help you think like an effective altruist: How many people benefit, and by how much? Is this the most effective thing you can do? Is this area neglected? What would have happened otherwise? What are the chances of success, and how good would success be? Now it’s time to examine how we apply those questions to the real world and put effective altruism into action. That is the subject of Part II.

The third organisation is GiveDirectly. Its programme is simple: it transfers money from donors directly to some of the poorest people in Kenya and Uganda who are then free to use that money however they wish. Using what is called the M-Pesa system, cell phones are used as makeshift bank accounts, thereby enabling an easy transfer of money from foreign bank accounts to the poor. GiveDirectly uses satellite images to find households with thatched roofs (a strong indicator of poverty, compared to iron roofs) and then contacts those households to discuss the programme. If the household is willing, GiveDirectly transfers them a lump sum of $1,000, which is equal to a little more than one year’s total income for that household. In their words: Recipients use transfers for whatever is most important to them; we never tell them what to do. An independent evaluation of our work in Kenya by Innovations for Poverty Action found that recipients use transfers for a wide variety of purposes that on average generate large income gains. Common uses range from buying food to investing in tangible assets such as housing and livestock to investing in children’s education.

Below are the five questions I think any donor should ask before deciding where to give. They are based on the criteria used by the charity evaluator GiveWell, which has spent the last eight years investigating which charities improve lives the most with the donations they receive: What does this charity do? How many different types of programmes does it run? For each of these programmes, what exactly is it that this charity does? If it runs more than one programme, why is that? How cost-effective is each programme area? Is the charity focused on one of the most important causes? How cost-effective does the evidence suggest the programme to be? How robust is the evidence behind each programme? What is the evidence behind the programmes that the charity runs? Are there trials showing that the programme is effective? Does the charity rigorously monitor and evaluate the success of its programmes? How well is each programme implemented? Do the leaders of the charity have demonstrated success in other areas? Is the charity highly transparent? Does it acknowledge mistakes that it’s made in the past? What are the alternative charities you could give to? Are there good reasons for supposing that this charity is better than others? Does the charity need additional funds? What would additional funding be used to do? Why haven’t other donors already funded the charity to the point it can’t use extra money?

Diarrhoea is a major problem in the developing world, killing 760,000 children every year, primarily through dehydration. (For comparison, that’s a death toll equivalent to five jumbo jets crashing to the ground every day, killing everyone on board.) A significant number of those deaths could be avoided through simple improvements to sanitation and hygiene, like more regular hand washing with soap.

One of the most damning examples of low-quality evidence concerns microcredit (that is, lending small amounts of money to the very poor, a form of microfinance). Intuitively, microcredit seems like it would be very cost-effective, and there were many anecdotes of people who’d received microloans and used them to start businesses that, in turn, helped them escape poverty. But when high-quality studies were conducted, microcredit programmes were shown to have little or no effect on income, consumption, health, or education. Rather than starting new companies, microloans are typically used to pay for extra consumption like food and healthcare, and the rate of interest on them is often very high. There’s even concern that they can cause harm by providing a tempting short-term income boost at the expense of longer-term financial security: people take out a loan in order to pay for food or healthcare costs of family members, but then enter debt that they are unable to repay. The latest evidence suggests that, overall and on average, microlending does have a small positive improvement on people’s lives, but it’s not the panacea that the anecdotes portray. With these warnings at the top of our

Because transferring cash is such a simple idea, and because the evidence in favour of cash transfers is so robust, we could think of them as the ‘index fund’ of giving. Money invested in an index fund grows (or shrinks) at the same rate as the stock market; investing in an index fund is the lowest-fee way to invest in stocks and shares. Actively managed mutual funds, in contrast, take higher management fees, and it’s only worth investing in one if that fund manages to beat the market by a big enough margin that the additional returns on investment are greater than the additional management costs. In the same way, one might think, it’s only worth donating to charitable programmes rather than simply transferring cash directly to the poor if the other programmes provide a benefit great enough to outweigh the additional costs incurred in implementing them. In other words, we should only assume we’re in a better position to help the poor than they are to help themselves if we have some particularly compelling reason for thinking so.

GiveDirectly What does it do? Provides direct unconditional cash transfers to poor households in Kenya and Uganda. Estimated cost-effectiveness? Fairly cost-effective. $1 in donations results in 90¢ delivered to the poorest households in Kenya and Uganda; this leads to increases in investment, consumption, education spending, and subjective wellbeing. Robustness of evidence? Extremely robust. There have been a large number of studies of cash transfers proving efficacy, and GiveDirectly has collaborated with independent evaluators to conduct a randomised controlled trial of its own programme. Implementation? Extremely well implemented. The charity is run in part by a leading development economist. It is very open, transparent and self-sceptical. Room for more funding? Extremely large. It estimates it could productively use an additional $35 million in 2015, and expects to receive about $15 million in that time. The potential for GiveDirectly to scale up beyond that in future years is very great.

Development Media International What does it do? Produces and runs radio shows to educate people in Burkina Faso on basic health matters, with plans to cover DR Congo, Mozambique, Cameroon and Côte d’Ivoire. Estimated cost-effectiveness? Extremely cost-effective. According to Development Media Internationals’ interpretation of previous studies, and its own mathematical model, its cost-effectiveness is on the order of $10/QALY. Robustness of evidence? Fairly robust. It is collaborating with external investigators to conduct a randomised controlled trial on its own programme, but has not yet gathered final mortality data; current data is based on self-reporting. Implementation? Very well implemented. CEO Roy Head has extensive experience in running radio programmes in developing countries, and DMI works with leading epidemiologists to monitor their effectiveness. The charity has been open, transparent and self-sceptical. Room for more funding? Very large. In order to scale up to four more countries, it believes it could use about $10 million in 2015, and expects to receive $2–4 million.

That means that even if buying Fairtrade was a good way of paying farmers more, you might make a bigger difference by buying non-Fairtrade goods that are produced in the poorest countries rather than Fairtrade goods that are produced in richer countries. Because Costa Rica is ten times richer than Ethiopia, $1 is worth more to the average Ethiopian than several dollars is to the average Costa Rican. Second, of the additional money that is spent on Fairtrade, only a very small portion ends up in the hands of the farmers who earn that money. Middlemen take the rest. The Fairtrade Foundation does not provide figures on how much of the additional price reaches coffee produces, but independent researchers have provided some estimates. Dr Peter Griffiths, an economic consultant for the World Bank, worked out that for one British café chain, less than 1% of the additional price of their Fairtrade coffee reached coffee exporters in poor countries. Finnish Professors Joni Valkila, Pertti Haaparanta and Niina Niemi found out that, of Fairtrade coffee sold in Finland, only 11% of the additional price reached the coffee-producing countries. Professor Bernard Kilian and colleagues from INCAE Business School found that, in the US, while Fairtrade coffee would sell for $5 per pound more than conventional coffee, coffee producers would receive only 40¢ per pound, or 8% of that increased price. In contrast, remember that, if you donate $1 to GiveDirectly, 90¢ ultimately reaches the poor. F...

Another major area of ethical consumerism is ‘green living’. Per person, UK citizens emit nine metric tons of carbon dioxide equivalent every year. (Recall that carbon dioxide equivalent, or ‘CO2eq’, is a way of measuring your carbon footprint that includes greenhouse gases other than carbon dioxide, like methane and nitrous oxide. For example one metric ton of methane produces as much warming as twenty-one metric tons of carbon dioxide, so one metric ton of methane is twenty-one metric tons of CO2eq.) As we’ve seen, climate change is a big deal. It’s therefore natural to want to do something about it, and the obvious way is to move to a lower-carbon lifestyle. Sadly, many popular ways of reducing your greenhouse gas emissions are rather ineffective. One common recommendation is to turn off or shut down electronic devices when you’re not using them, rather than keeping them on standby. However, this achieves very little compared to other things you could do: one hot bath adds more to your carbon footprint than leaving your phone charger plugged in for a whole year; even leaving on your TV (one of the worst offenders in terms of standby energy use) for a whole year contributes less to your carbon footprint than driving a car for just two hours. Another common recommendation is to turn lights off when you leave a room, but lighting accounts for only 3% of household energy use, so even if you used no lighting at all in your house you would save only a fraction of a metric ton...

Cool Earth was founded in 2007 in the United Kingdom by businessman Johan Eliasch and MP Frank Field, who were concerned with protecting the rainforest and the impact that deforestation might have on the environment. The charity aims to fight global warming by preventing deforestation, primarily in the Amazon. It uses donated money to help develop rainforest communities economically to a point where they do better by not selling their land to loggers. Cool Earth does not buy rainforest directly; instead, it provides economic assistance to local communities, helping the people who inhabit the rainforests establish more profitable ventures than selling trees. This involves, among other things, working to secure property rights, improving community infrastructure and connecting the inhabitants of the forests with markets where they can sell their produce at good prices. The work Cool Earth does therefore incidentally improves the lives of those living in the rainforest while working to prevent climate change.

Using this figure, the average American adult would have to spend $105 per year in order to offset all their carbon emissions. This is significant, but to most people it’s considerably less than it would cost to make large changes in lifestyle, such as not flying. This suggests that the easiest and most effective way to cut down your carbon footprint is simply to donate to Cool Earth.

Things may even be worse than that, however. There’s some reason to believe that the rise in ethical consumerism could even be harmful for the world, on balance. Psychologists have discovered a phenomenon that they call ‘moral licensing’ that describes how people who perform one good action often compensate by doing fewer good actions in the future. For example, in a recent experiment participants were told to choose a product from either a selection of mostly ‘green’ items (like an energy-efficient light bulb) or from a selection of mostly conventional items (like a regular light bulb). They were then told to perform a supposedly unrelated visual perception task: a square box with a diagonal line across it was displayed on a computer screen, and a pattern of twenty dots would flash up on the screen; the subjects had to press a key to indicate whether there were more dots on the left or right side of the line. It was always obvious which was the correct answer, and the experimenters emphasised the importance of being as accurate as possible, telling the subjects that the results of the test would be used in designing future experiments. However, the subjects were told that, whether or not their answers were correct, they’d be paid 0.5¢ every time they indicated there were more dots on the left-hand side of the line, and 5¢ every time they indicated there were more dots on the right-hand side. They therefore had a financial incentive to lie, and they were alone so they knew...

First, and most simply, most people don’t have passions that fit the world of work. In one study of Canadian college students, it was found that 84% of students had passions, and 90% of these involved sport, music and art. But by looking at census data, we can see that only 3% of jobs are in the sport, music and art industries. Even if only half the students followed their passion, the majority would fail to secure a job. In these cases, ‘doing what you’re passionate about’ can be actively harmful.

Rather, passion grows out of work that has the right features. This was true even of Steve Jobs. When he was young, he was passionate about Zen Buddhism. He travelled in India, took plenty of LSD, shaved his head, wore robes and seriously considered moving to Japan to become a monk. He first got into electronics only reluctantly, as a way to earn cash on the side, helping his tech-savvy friend Steve Wozniak handle business deals while also spending time at the All-One commune. Even Apple Computers’ very existence was fortuitous: while Jobs and Wozniak were trying to sell circuit boards to hobbyists, the owner of one local computer store said he would only buy fully assembled computers, and they jumped at the chance to make more money. It was only once they started to gain traction and success that Jobs’s passion for Apple and computing really bloomed.

Beyond track record, if you want to predict how well you’ll perform, the first step is to learn as much about the work as you can. Go and speak to people in the job. Ask what traits they think are most important to success and see how you measure up. Ask about the main reasons people end up leaving the job. Find out how people who are similar to you have performed in the past. Look at whether you think you’d find the work satisfying based on the factors mentioned earlier. The ‘follow your passion’ slogan assumes it’s as easy as looking inward to figure out what you ought to be doing. In contrast, identifying a job with what we call good ‘personal fit’ involves finding out as much about a job as you can, because it’s features of the job itself that are much more important in determining how well you succeed and enjoy your work than whether that job corresponds with your pre-existing passions.

This has three implications. First, it means you should think of your career as a work in progress. Rather than having a fixed career plan, try to have a career ‘model’ – a set of provisional goals and hypotheses that you’re constantly revising as you acquire new evidence or opportunities. It’s better to have a bad plan than no plan, but only if you’re open to changing it. Second, find out where you’re uncertain, then reduce that uncertainty. Before making a decision, don’t merely try to weigh up all the pros and cons as you currently see them (though that is a good thing to do). Ask yourself: ‘What is the single most important piece of information that would be most useful for my career decision? Now, what can I do in order to gain that information?’ Third, test yourself in different paths. In science you try to test hypotheses. Similarly, if you can, you should try to run ‘tests’ of different career plans; this is important because it’s often very difficult to predict which careers will work out and which won’t. For example one person we coached started an internship at an asset-management firm. Having no experience in the field, she didn’t know whether she’d like it, but she guessed she wouldn’t. It turned out she hated the job. In a sense, she ‘failed’. But that failure meant she could be much more confident in pursuing a different (academic) path, instead. Her bad experience was very valuable.

Research When Norman Borlaug was awarded the Nobel Peace Prize in 1970, the committee suggested that he’d saved one billion lives. Was he a politician? Or a military leader? Or a superhero? No, he was a fairly regular guy from Iowa who worked in agricultural research. He wasn’t a typical academic: his credentials were limited and he used techniques that had been available to the Victorians. Moreover, the innovation that made his name was rather boring – a new type of short-stem disease-resistant wheat. That wheat, however, was able to radically increase crop yield across poor countries. It helped to cause the ‘green revolution’. Even after taking into account the fact that similar innovations may have happened even if he hadn’t done his research, Borlaug’s impact should be measured in the prevention of tens of millions of deaths. In terms of researchers with impact, Borlaug isn’t a lone example: in any list of the most influential people of all time, scientists and researchers make up a large percentage. Scientists who have clearly had a huge positive effect on the world include Fritz Haber and Carl Bosch, who invented synthetic fertiliser; Karl Landsteiner, who discovered blood groups, thus allowing blood transfusions to be possible; Grace Eldering and Pearl Kendrick, who developed the first whooping cough vaccine; and Françoise Barré-Sinoussi and Luc Montagnier, who discovered HIV. In each of these cases, even after taking into account that these developments would have ...

This means you should try to volunteer only in ways that cost an organisation relatively little. For example by contributing high-quality work to Wikipedia, you can provide a significant benefit to many people at almost no cost to others. Some organisations also have opportunities that are designed to take on board volunteers with little cost. Mercy for Animals, for example, is a vegetarian advocacy organisation. It has volunteers contact people who have commented on videos on factory farming on Facebook. These volunteers then discuss the option of going vegetarian with them. This provides a significant benefit while costing the charity very little in management time. An alternative route to having an impact without imposing a burden on charities is to work additional hours instead of volunteering and donate the money you make. However, you don’t need to limit yourself to this. Instead, I’d encourage you to think about volunteering primarily in terms of the skills and experiences you’ll gain, which will enable you to have a greater impact later in your life. Because the total time you’ll spend volunteering will be only a tiny fraction of the total time you’ll spend on your career, the impact volunteering has on other areas of your life will generally be much greater than the impact you have via the volunteering itself.

On the framework I propose, you can compare causes by assessing them on how well they do on each of the following three dimensions: First, Scale. What’s the magnitude of this problem? How much does it affect lives in the short run and long run? Second, Neglectedness. How many resources are already being dedicated to tackling this problem? How well allocated are the resources that are currently being dedicated to the problem? Is there reason to expect this problem can’t be solved by markets or governments? Third, Tractability. How easy is it to make progress on this problem, and how easy is it to tell if you’re making progress? Do interventions within this cause exist, and how strong is the evidence behind those interventions? Do you expect to be able to discover new promising interventions within this cause? If we’re thinking about contributions of time rather than just money, then there is a fourth important dimension: Personal fit. Given your skills, resources, knowledge, connections and passions, how likely are you to make a large difference in this area?

This is an easy consideration to forget. If something seems like a huge problem – perhaps the biggest problem in the world – it is natural to think one should focus on it. But if that problem already has a large amount of resources invested in it, then additional resources might be better spent elsewhere. For example HIV/AIDS, tuberculosis and malaria traditionally received much more attention than conditions like intestinal worms. One reason for this, I think, is that these other conditions cause a much greater amount of ill health (measured in number of deaths, or QALYs lost) than intestinal worms do, and thereby attracted a disproportionate share of attention. However, precisely because intestinal worms had much less attention, the cheapest and most effective ways of treating them were still available. In fact, it wasn’t until Alan Fenwick, executive director of the Schistosomiasis Control Initiative, coined the term ‘Neglected Tropical Diseases’ that these conditions became more prominent in the discussion of global health. The term had two benefits. First, it classified a wide range of conditions under one heading. This meant that, even though the burden of disease from schistosomiasis, for example, was small compared to the global burden from HIV/AIDS, the global burden of disease from all neglected tropical diseases was comparable to the global burden from HIV/AIDS. Second, the name highlighted the fact that these diseases were neglected. When you read the rest of t...

What promising organisations are working on it? The Nuclear Threat Initiative (accepts donations) works on a variety of projects to reduce the spread of nuclear, biological and chemical weapons. The Future of Humanity Institute and The Centre for the Study of Existential Risk (both accept donations) are interdisciplinary research institutes at the Universities of Oxford and Cambridge, respectively, that assess the magnitudes of global catastrophic risks and try to develop risk-mitigation strategies.

For your birthday, instead of presents you could ask for donations to a highly effective charity, creating a webpage on Causevox.com; Charity Science, a fundraising website set up by two people in the effective altruism community, helps you to do this on their Take Action page. If it’s the holiday giving season, you could offer to match any donations made by your colleagues up to a certain amount. You could organise discussion groups on career choice, or cause selection, or ethical consumerism.

The five key questions of effective altruism How many people benefit, and by how much? Like James Orbinski, the doctor who engaged in triage during the Rwandan genocide, we need to make hard decisions about who we help and who we don’t; that means thinking about how much benefit is provided by different activities. The quality-adjusted life year, or QALY, allows us to compare the impact of different sorts of health programmes. Is this the most effective thing you can do? The very best health and education programmes are hundreds of times better than ‘merely’ very good programmes. Smallpox eradication did so much good that it alone shows development aid to be highly cost-effective on average. Is this area neglected? Natural disasters get far more funding than ongoing causes of death and suffering such as disease; for that reason, disaster relief usually isn’t the most effective use of funds. Diseases such as malaria that affect people in the developing world get far less funding than conditions like cancer; for that reason you have a much bigger impact treating people with malaria than with cancer. What would have happened otherwise? After going through the Scared Straight programme, juveniles were more likely to commit crimes than they would have done otherwise, so the programme did harm overall. In careers like medicine, you’re sometimes simply doing good work that would have happened anyway; if you earn to give, however, you make a difference that wouldn’t otherwise have...