How to make a difference: Part 2 Can one person make a difference? What the evidence says

It’s easy to feel like one person can’t make a difference. The world has so many big problems, and they often seem impossible to solve.

So, when we started 80,000 Hours — with the aim of helping people do good with their careers — one of the first questions we asked was, “How much difference can one person really make?”

We learned that many of the ways people most often try to do good have less positive impact than you might at first think. Other ways, meanwhile, have allowed people to achieve an extraordinary impact.

In other words, one person can make a difference — but it might require doing something a little unconventional.

Reading time: 10 minutes

How much difference do doctors actually make?

People who want to help others often become doctors, and around 20% of all university graduates work in healthcare of some kind.¹ One of our early readers, Dr Greg Lewis, did exactly that. “I want to study medicine because of a desire I have to help others,” Greg wrote earnestly on his university application, “and so the chance of spending a career doing something worthwhile I can’t resist.”

But how much difference does becoming a doctor really make? We teamed up with Greg to find out.

Since a doctor’s primary purpose is to improve health, Greg tried to figure out how much extra health one doctor actually adds. It turned out to be far less than we expected:

First, he found researchers largely agree that medicine as a whole has only increased life expectancy by a couple of years. Most gains in life expectancy over the past 100 years have been due to better nutrition, improved sanitation, increased wealth, and other factors.

Second, doctors are only one part of the medical system. Healthcare relies on nurses and hospital staff, not to mention the hospital buildings, drugs, and equipment. The impact of medical treatment is shared among all of these elements.

Third, there are already a lot of doctors in rich countries; usually enough to cover the most crucial procedures. Additional doctors will only enable us to carry out procedures that deliver less significant and certain results.

This point is illustrated by the chart below, which compares the impact of doctors in different countries. The y-axis shows the amount of ill health in the population, measured in disability-adjusted life years (DALYs) per 100,000 people. One DALY equals one year of life lost due to ill health, whether through reduced lifespan or reduced quality of life. The x-axis shows the number of doctors per 100,000 people.

You can see that the curve goes nearly flat once you have more than 150 doctors per 100,000 people. After this point, which almost all rich countries reach, additional doctors only tend to have a small impact. The UK, where Greg was planning to work, has about 320 doctors per 100,000 people.²

Fourth, if you become a doctor, you’ll likely be taking the place of someone else who would have gone to medical school. This means you’re probably not even increasing the number of doctors available to patients, because the number of medical students won’t change. Instead, your impact mainly comes from increasing the average skill level of people who become doctors — assuming you are more proficient at the job than the person who would have been accepted otherwise.

Putting all of these factors together, Greg estimated that over the course of an entire career an average doctor in the UK will enable their patients to live a combined 100 extra years of healthy life, either by extending their lifespans or by improving their overall health. There is, of course, a fair amount of uncertainty in this figure, but even if it’s quite wide of the mark, the real figure is unlikely to be more than 10 times higher (and it could also be a lot lower).

Using a standard conversion rate of 30 extra years of healthy life to one ‘life saved,’ that impact is equivalent to about three lives saved. This is clearly a significant and desirable impact; however, it’s far less than many people expect. It amounts to less than one life saved per decade.

If you become a doctor in a rich country like the US, UK, or Australia, you may well do more good than you would have done in many other jobs. And if you are an exceptional doctor, you’ll have a bigger impact than these averages. But it probably won’t be a huge impact. In fact, in part three, we’ll show how almost any university graduate can do more to save lives than a typical doctor in a rich country.

You might wonder about becoming a doctor in rural India or Nigeria, where there are fewer than 40 doctors per 100,000 people. The earlier graph suggests your impact would be around 2–10 times higher, which would mean saving 6–30 lives over your career. This is significantly better, but we think there are ways to have a greater impact still.

Motivated by these findings, Greg decided to leave clinical medicine. He ended up working in biosecurity, aiming to prevent a future pandemic, for reasons we’ll explain in part five. But before that, it’s important to clarify that saving lives isn’t all that matters — it’s just one way to have a positive impact.

What does it mean to “make a difference”?

Many people talk about “making a difference,” “changing the world,” or “doing good,” but few stop to define what they mean by that. Here’s the definition we’re going to use: your positive impact is given by:

The number of people whose lives you improve, how much you improve them, and how long the effects last.³

This means you can increase your impact in three ways:

1. By helping more people

2. By helping the same number of people to a greater extent

3. By doing something which has benefits that last a longer time

These multiply together. Taking just the first two, we could picture your total impact as in the following chart:

To get one step nerdier, you can imagine adding a third dimension: time, extending out of the page. Your impact would be indicated by the total volume. Time is especially important because many of our actions could affect future generations.

What “helping people” consists of is left intentionally broad. We take it to include anything that enables people to live happier, healthier, more fulfilling lives, which are more in line with their wishes, free from avoidable suffering, and filled with rich relationships, understanding, beauty, excitement, and so on.

You can create your own more specific definition if you like, but because most definitions overlap so much in their practical implication, we usually don’t find it matters hugely. If you’d like to dig deeper, see our discussion of what wellbeing consists of.

Stepping back a bit, philosophers have debated what it means to lead a moral life for millennia, but just three answers have come to dominate:

1. Having good character: acting bravely, wisely, kindly, and honestly

2. Doing what’s right: respecting the rights of others and not harming them

3. Making the world better: helping others and creating more of what’s of value⁴

The difference you make is just the third of these. Philosophers like to debate which perspective ultimately matters most, but from a practical point of view, we think you should aim to uphold all three: cultivate good character, respect the rights of others, and try to make the biggest difference you can.⁵

It turns out that once you’ve eliminated careers that violate rights or compromise your character, there are still huge differences in the impact of different paths, so in practice this becomes the deciding factor.

Living a moral life is also just one part of a good life, as most people would understand it. You probably have important personal, artistic, or spiritual goals in addition to your moral ones. But, given the enormous opportunities to help others in the world today, we think moral goals are especially important.

Who made the biggest difference in history?

Just because the average doctor in the West has relatively little impact, that doesn’t mean every doctor does. In fact, some doctors have been among the people who made the biggest difference in world history.

By 1968, it was known that a solution of glucose and salt, administered via feeding tube or intravenous drip, could prevent death from cholera. But millions of people were still dying every year from the disease. While working in a refugee camp on the border of Bangladesh and Burma, the American physiologist Dr David Nalin sought to turn this new insight into a therapy that could be effectively deployed in low-income rural areas.

Nalin demonstrated in a study that simply drinking a solution of glucose and salt made at the right concentration, and consumed at the right rate, could be almost as effective as delivery via feeding tube or IV. This meant the treatment could be delivered with no equipment using extremely cheap, widely available ingredients.

Since then, this astonishingly simple treatment has been used to treat all kinds of diseases that cause death by dehydration around the world. The annual rate of child deaths from diarrhoea has plummeted from around 5 million to 1.5 million. Researchers estimate that the therapy has saved over 50 million lives to date, mostly children’s.⁶

If Nalin had not been around, someone else would, no doubt, have discovered this treatment eventually. However, even if we imagine that he only sped up the roll-out of the treatment by five months, his work alone would have saved about 500,000 lives. This is a very approximate estimate, but it makes his impact more than 100,000 times greater than that of an ordinary doctor:

Even within medical research, Nalin is far from the most extreme example of a high-impact career. Until the start of the 20th century, blood transfusions were often fatal. The donated blood was sometimes rejected by the patients’ bodies, and nobody understood why.

The discovery of blood groups by the Austrian-American biologist and physician Dr Karl Landsteiner made it possible to ensure that people were only given blood from their own group, enabling successful transfusions, and likely saving tens of millions of lives.⁷

It’s not only doctors who have been this impactful. Later in the guide, we’ll cover the stories of a hugely impactful mathematician and particularly brilliant bureaucrat. Or take Roger Bacon and Galileo, who pioneered the scientific method — without which none of the discoveries we covered above would have been possible. Or consider the story of Stanislav Petrov.

The unknown Soviet lieutenant colonel who saved your parents’ and grandparents’ lives

Petrov was a lieutenant colonel in the Soviet Army during the Cold War. In 1983, he was on duty in a Soviet command bunker near Moscow when early warning systems appeared to detect an incoming missile strike from the United States. Protocol dictated that Petrov report the incoming strike, and that on receipt of the alert, a return strike be launched.

But Petrov didn’t report it. He reasoned that the number of missiles was too small, suggesting computer error. Instead, he deliberately disobeyed protocol.

If there had been a return strike by the Soviets, there’s a reasonable chance the US and the Soviet Union would have ended up engaged in an all-out nuclear war. That would probably have killed around 50 million people in the initial exchange. Next, smoke from burning cities would have entered the atmosphere, blocking out sunlight and cooling global temperatures for several years, making it far harder to grow crops. Researchers estimate that the resulting famine would likely have led to billions of deaths.⁸

So Petrov may well have saved your parents’ and grandparents’ lives. We could roughly quantify his impact as having avoided a billion unnecessary deaths. But this could be an underestimate, because a nuclear war would also have devastated scientific, artistic, economic, and all other forms of progress, leading to a much greater loss of wellbeing in the long run. Even using this lower estimate, however, Petrov’s impact still dwarfs that of Nalin and Landsteiner.

What do these differences in impact mean for your career?

Some careers can make a huge difference. And a few have made vastly more difference than others. Some of this is due to luck. The people we’ve mentioned were in the right place at the right time, giving them the opportunity to have an impact they might not have otherwise had. You can’t guarantee you’ll make an important medical discovery.

But it wasn’t all luck. Landsteiner and Nalin chose to apply their medical knowledge to some of the most harmful health problems of their day. Similarly, it was foreseeable that someone high up in the Soviet military during the Cold War might be called upon to make some high-stakes decisions.

What does this mean for you? People often wonder how they can “make a difference,” but if some careers can result in thousands of times more impact than others, this isn’t quite the right question.

Instead, ask yourself: of the options open to me, which might make the most difference?

Or alternatively: what can I do to give myself the best chance of having an unusually impactful career?

Framing the question this way is crucial because, if the highest-impact careers achieve so much more than average, then a small increase in your chances of landing one means a great deal in terms of your impact on the world.

These examples also show that the highest-impact paths might not be the most obvious ones. Becoming an officer in the Soviet military doesn’t sound like the best career for a would-be altruist, but Petrov probably did more good than our most celebrated leaders, not to mention our most talented doctors.

It’s not easy to have a big impact, but there’s a lot you can do to increase your chances. That’s what we’ll cover in the next couple of sections, starting with how almost anyone reading this can do more good than a doctor.

Read next:  Part 3: 3 evidence-based ways anyone can have a real impact, no matter your job

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