Hi Professor Cowen, I am a loyal MR reader and I wondered if you could comment on the following situation: I am a 3rd year medical student, and for the purposes of this question, let’s assume I have equal interest and ability in the various medical specialties. In order to create the greatest good for the greatest number of people through my work in medicine (i.e., the highest return to society), what specialty should I pursue? I should add that, although I intend to practice in the U.S., I am open to devoting as much of my free time/vacation as possible to pro bono medical activities, and further, that I wish to do the interventions myself (instead, for example, or just making lots of money and then donating the proceeds to some other charitable activity). In attempting to answer this question, I’ve been looking at DALYs and QALYs associated with various medical interventions (e.g., cataract surgery). Am I going about answering this question the right way? Any thoughts? An interesting corollary would be asking what job, in any field, has the highest return to society. Is there any literature on this?

The fundamental institutional failure to overcome is that many lives “out there” are pretty happy, and very much worth living, but those individuals do not have enough money to afford reasonable doctors. If you are seeking to maximize social welfare, look to step into some of these gaps.

But which gap in particular?

The second binding constraint, in my view, is that most people won’t in fact go through with their plan to do a lot of social good. That means you too. So you wish to seek out a form of do-gooding which is incentive-compatible over the long run, or in other words which is fun for you or rewarding in some other way. This second consideration is likely to prove decisive.

For instance you might decide the fight against dengue (just an example to make a point, not an actual net assessment) is the way to go, based on a narrow cost-benefit analysis. But it is hard as a field worker to really, fully protect yourself against dengue. And getting dengue can be very bad indeed. As you age, the pressures not to go into the field will mount. You might do more good by pledging your efforts to fight a malady which you can help fix without so much direct risk or exposure to yourself, let’s say infant mortality.

You will note a difference here between pledges of individual effort and pledges of money. A money pledger, thinking in game-theoretic Nash terms, will realize that effort pledgers will resist the fight against dengue. That is all the more reason why throwing money at the fight against dengue may bring high returns, namely that at the margin not enough is being done from the side of volunteer and quasi-volunteer labor. (In general this distinction creates a problem with talking up one kind of cause over another, namely that labor and money face differing incentives and should hear different messages of encouragement.)

You will note also that in a second best optimum, field workers will appear to be “consuming too many perks.” At the same time, donated funds should be trying to push field workers out of their comfort zones, at least on the margin.

I would add two final points. First, if you have a reasonable chance of being a research superstar, that may be the path to follow.

Second, if you are not already attached, spent time cultivating social circles (aid work, World Bank, vegetarians, etc.) where you are likely to meet a partner or spouse who will support a similar vision to help the world.

Addendum: David Henderson adds comment.