How can doctors do the most good? An interview with Dr Gregory Lewis

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Gregory Lewis is public health doctor training in the east of England. He studied medicine at Cambridge, where he volunteered for Giving What We Can and 80,000 Hours. He blogs at The Polemical Medic. This interview was conducted as part of the research I did for Will MacAskill’s book, Doing Good Better: How Effective Altruism Can Help You Make a Difference. Greg’s story is discussed in the fourth and fifth chapters of that book.

Pablo Stafforini: To get us started, can you tell us a bit about your background, and in particular about your reasons for deciding to become a doctor?

Gregory Lewis: Sure. I guess I found myself at the age of 14 or so being fairly good at science and not really having any idea of what to do with myself. I had some sort of vague idea of wanting to try to make the world a better place, in some slightly naive way. So I sort of thought, “What am I going to do with myself?” And my thoughts were pretty much verbatim, “Well, I’m good at science and want to do good. Doctors are good at science and they want to do good. Therefore, I want to be a doctor.” So based on that simple argument, I applied to medical school, got in, spent the following six years of my life in medical school qualifying as a doctor, and here I am today.

Pablo: I suppose that at some point between the age of fourteen and the present you changed your mind to some degree about the kind and amount of good that doctors could do. Can you elaborate on that?

Greg: Yes. One of my interests outside medicine was philosophy – I almost studied philosophy at university, but I thought I could do more good as a doctor. It was through this I read Peter Unger’s book Living High and Letting Die. This book opened my eyes to the importance and moral significance of giving substantially to charity, and I took this message to heart. But I didn’t really link it up with what I’d planned in my career: I thought I would heal the sick (if you’ll excuse the expression) in my day job, and the good I would do by giving a lot to charity would be an added bonus.

It took a couple of years, and coming into contact with people like Toby Ord and Will MacAskill, to begin to put these things together, and look again at my plans to be a doctor. How much good did doctors really do and (more importantly) how did it stack up in comparison with all the other things I could do instead? So I began to look at this question and found (somewhat to my disappointment) that working as a doctor doesn’t fare well in this sort of comparison.

Pablo: You mention Unger’s book, and I recall that in that book the argument for earning to give is briefly sketched. Did you notice that argument when reading the book, or did you just focus on the message that you should be donating a big chunk of the money you’d expect to earn in your current career (as opposed to switching to an even more lucrative career)?

Greg: Yes, I remember reading those couple of paragraphs where he suggests that philosophers should consider moving out of academia into corporate law or more lucrative fields, so that they would have more money to give away. That sounded right to me back then, but I didn’t really see medicine at the time as an ‘earning to give’ career—I thought the direct impacts of medicine were substantial, so a medical career got the ‘best of both worlds’, and the money I would give away would be an ‘added bonus’ to the direct work as a medical doctor. It took getting more involved with the effective altruism community to think I should try and combine these two worlds, and that I should try and weigh up how much good doctors do versus how much good donations do, and plan my career accordingly.

Pablo: So when you started to think more systematically about the amount of good that doctors could do, do you think you encountered any internal resistance to the possible conclusion that this amount might not be as high as you had assumed initially?

Greg: The seeds of scepticism were sown fairly early in my training. Doctors themselves generally are fairly cynical of the good they do, and when they talk about ‘healing the sick’, it is with tongue firmly in cheek. One conversation I remember clearly (and with retrospect I wish I paid attention to more) was talking to a doctor in paediatrics, who said something along the lines of, “I don’t ever feel like I’m saving lives or making a big difference, because although I might be the guy giving the life-saving treatments, if I wasn’t there they would have called the doctor just down the hall, who would have done exactly the same as I.”

I gradually internalized this more realistic view on how much good I could do as a doctor. This was somewhat disappointing to me, but I wasn’t that phased by it. Maybe the world is just set up that it’s really hard to make a big difference, and if the best I could hope for was to make a more modest contribution, that is still definitely ‘worth it’, and (like many other doctors) I decided my prior zeal to heal the sick and save the world was quixotic, immature, and naive: “The mark of an immature man is the desire to die nobly for a cause, whilst the mark of the mature man is the desire to live humbly for one.” I flirted with the idea of working for Médecins Sans Frontières (MSF) or abroad, but I wasn’t thinking systematically.

So one of the major upsides of reading Living High and Letting Die was finding out my 17 year old self wasn’t so unrealistic in hoping to save hundreds or thousands of lives—things that good are within our reach. The downside was this would happen through a very different channel. Rather than 17-year-old me’s vainglorious visage of (thousands of times over!) striding in, white coat billowing, and saving some stricken patient with my cleverness, it would be me posting a cheque or clicking a bank transfer: I’d know abstractly that this would do so much good, but I wouldn’t be able to point to the person it was that I helped. As it turns out, that’s no big deal — especially compared to the sheer magnitude of good done.

Pablo: Your conclusion that you wouldn’t in your capacity as a doctor be doing as much good as alternative paths to impact appears to involve both a premise about the amount of good doctors typically do and a premise about the amount of good that such people can do in other ways. That is, you seem to be claiming that doctors do less good directly than people assume, but also that people, including doctors, can do much more good than they think by donating to the right causes. Is that correct?

Greg: Yes. The major upshot of the work I’ve done into how much good a doctor does is that the average doctor probably saves around a handful of lives over their career. So that’s bad news for medics. By contrast, giving fairly small amounts to charity can save hundreds of lives (or maybe more) over your working life, and that’s good news for everyone!

Pablo: Let’s zoom in on your work about the good doctors do. Insofar as it’s possible to discuss these issues in an informal interview, without having all the relevant figures in front of us, can you sketch the argument for the conclusion that a doctor saves about 200 DALYs over the course of his or her career?

Greg: Sure. I started looking at the research literature expecting there would be a lot of work done on the ‘return’ of having more doctors—I figured this would be important to running a health system, or something more introspective members of the profession would have wanted to find out. As it happened, there was basically no work looking at the question: “How much good does a doctor do?”

The closest is work by an epidemiologist called John Bunker: he and colleagues were looking at the question of how much of the dramatic gains in health and life expectancy in the western world could be attributed to medical treatment. Their strategy was to look at the few hundred or so commonest medical interventions: fixing broken bones, treating heart attacks, stuff like that. For each of these, they looked at clinical trials to see how much good each of those things did, and, by adding them together, work out how much good medicine as a whole does. You can extrapolate from their figures to many healthy life years (a measure of length and quality of life—you can think of 30 health years as ‘one life saved’) are added to the population by the medical profession, and then divide by the number of doctors to get the ‘years added per doctor’ This is about 2250 health-years saved per medical career—that’s pretty good, about 80 lives.

There are several reasons to suspect this is an overestimate. One of the big ones is that the difference of a doctor should be on the margin. Although the first few doctors should be able to make a massive difference, subsequent doctors (like being the 170001st in the UK) should make a smaller difference, as all the easy ways to make people live longer and healthier should already be being done. If I were removed from my post, there wouldn’t be a ‘Greg shaped hole’ in the hospital where all my patients are not treated. Rather the remaining doctors will reallocate their tasks so only the least important things don’t get done.

So I began to attack this problem from the ‘top down’ rather than from the ‘bottom up’. Instead of compiling an inventory of medical treatment, I looked at aggregate measures of health and physician density, and looked at the relationship between them: looking at all the countries in the globe, did having more doctors per capita correspond to lower burdens of death and disability? The answer was ‘yes’, but there were diminishing returns. What I then did was fit a best line to this curve, and work out, if you were in the UK and you added one more doctor to the population, how much further along the curve do you go, and how much does disability fall? This figure is smaller, of the order of 400-800 health-years averted per medical career: 20 to 30 lives.

This figure, however, is also going to be an overestimate, because we implicitly ignore confounding factors—there are fairly obvious things that will increase both health and physician density, like wealth, sanitation, or education. Indeed, it’s received wisdom that these ‘social determinants of health’ are far more important than doctors. Happily, international data on these factors are also available, and one can try and tease apart these interrelationships by a technique called regression analysis. This gives a smaller figure still. The average doctor averts 200 or so DALYs per medical career—six lives or so.

There are all sorts of caveats with this sort of work—the data is fair but not great, it is fundamentally an observational study, and there’s always the spectre of unaccounted for confounds. Despite these concerns, I’d be surprised if this figure was off by an order of magnitude or more. If anything, this already fairly low estimate is also over-optimistic: two big factors would be that I’m ignoring counterfactuals and elasticity (if I never went to medical school, there wouldn’t be ‘one fewer doctor’, it would be more like ‘I would be replaced by the marginal candidate who just missed out on med school); even worse, physician density is serving as a proxy for ‘medical professional density’, from nurses, to hospital cleaners, to laboratory scientists. It’s implausible that doctors can take all of the credit, or even a majority of it. So even if doctors have the largest impact out of all the health professions, one is still looking at another adjustment down, by a factor of at least two

Pablo: How much could altruistically motivated doctors boost that figure if they targeted their efforts more intelligently, e.g. by working in a less developed country or in a more lucrative specialty?

Greg: That was the question I asked myself next: given this is the average impact of a doctor, how could I try to do better than average? This is tricky, as the ‘top down’ technique I used to find the average is too coarse-grained to answer these questions: there isn’t the data, for example, to work out whether the marginal impact of cardiologists is greater than colorectal surgeons, or things like that.

One strategy could be to exploit the ‘diminishing returns’ effect and go somewhere where the curve is steeper and so there are increasing benefits to having ‘an additional doctor’—this really crudely models ‘a career spent working in MSF’ or with a similar NGO. This does give a bigger impact, by a factor of 10 or so.

However, the chequebook can likely beat the stethoscope, even one wielded by an MSF doctor. The average doctor in the UK will earn around 2.5 million pounds over their lifetime. Giving 10% of this to the right interventions will still ‘beat’ an additional doctor abroad. And one can always give more than 10%, and although that is hard, it may not be as hard as spending one’s career in the developing world.

The next question—going back to Unger—is whether there are particularly lucrative medical careers one could target with the aim of giving more away. And there are, at least when working in the Western world. To give the UK as an example, average consultant earnings by specialty vary by a factor of 3 or so, and the main determinant of this variation is the capacity that specialty has for private practice: you can’t really work privately as an emergency physician, but one can work wholly outside the NHS as a plastic surgeon. So medicine is a fairly good earning to give option, although it is worth noting that if earning to give ‘beats’ direct impact by a large margin, it perhaps would be even better to attempt to work in even more lucrative careers outside of medicine.

Finally, there are ‘peri-medic’ roles that could be really important but hard to quantify: the chief medical officer for the NHS (or for the WHO), the researcher who makes the breakthrough for a malaria vaccine could have massive impact, so much so that it might be worth attempting even if it is a very long shot and one is likely to achieve something far more modest. It’s pretty hard to quantify these considerations, but they look like career paths that could be even better than earning to give.

Perhaps the upshot is that direct work as a doctor is relatively small-fry compared to what you could do instead. Which ‘instead’, though, remains very difficult to work out.

Pablo: To wrap up, you mentioned that you are currently giving about 50% of your income to cost-effective charities. Can you elaborate on what motivated you to give away such a big portion of your income and whether you find that difficult on a personal level?

Greg: Sure. So, given what I’d read by Unger, and in philosophy more generally, giving a lot to charity seemed a bit of a moral no-brainer. On the one side, several lives in my first year of being employed (and several thousand over my career as my salary grows), and on the other side, not a huge amount. So I committed to give 10% of my earnings whilst I was a medical student.

It became even more of a no-brainer when I actually started working. I am privileged in all manner of ways, but not least in that I live without dependents in a modern liberal democracy with almost double the median income of my country, and so among the top few percent of the planet by wealth. I found living similarly (but still better) than I did as a medical student left me with almost half my paycheck. So I started giving 10%, and have steadily increased this month on month until now I’m giving about 50%.

It’s only at this larger proportion that there’s any real personal ‘sacrifice’ on my part: I now plan journeys in advance, keep a monthly budget, and don’t reflexively eat out whenever the opportunity presents itself. I also haven’t (as some of my colleagues have) got a BMW on franchise, or regularly holiday across the world. I don’t really miss these luxuries, especially as these sacrifices are made without choice by most people living in the UK (and the globe), including people who work much harder and longer than I do alongside me in hospital.

I’m still in the wealthiest 10% of people on the planet. More importantly, I still get to keep the things that really matter: family, friends, literature, music, a career that, even though it might not save the world, is immensely personally fulfilling and interesting. Even better, I am happy I am doing something significant in making the world go better. I think the 17 year old me who wanted to be a doctor would be happy, but surprised, at the doctor he turned into.

Pablo: Awesome. Thanks, Greg!