I've read an interview with Gregory Lewis on 80000 hours. He argued that due to counterfactual, doctors don't make a big difference because doctors are already highly competitive, so you don't make big impact especially if you work in rich countries. There's a problem: You can still make a difference by being a better and more patient doctor. I don't know the doctors in America, but in East Asia, not every doctors are good. Some just want to make money and they treat the patient poorly, making them suffer more.(such as misdiagnosis) So, if you can be a good doctor, the counterfactual case would be" You replace a worse doctor than you". I don't know how valuable would it be, but this shows doctors in rich countries may be more altruistic than normal careers. Also, you need to consider how prolonging one's lifespan influences his/her relatives' suffering. Some people feel desperate if their relatives pass away. Being a biology researcher may be more valuable than just being a clinical doctor in the long run, but, I think we may underestimate a doctor's impact.
The original 2012 post from Gregory Lewis tried to estimate this, and ends up estimating that a doctor can make a difference of "around 20 lives", excluding donations, which is a lot!
For other ways in which a doctor can have a lot of impact, you might be interested in Careers in medicine - a new path profile from Probably Good and High Impact Medicine.
Thanks a lot by the sharing the article (This is not the same as I saw on 80000). So Dr.Lewis thought about"replacing a worse doctor". There are some factors that would change the QALYs number: 1.Mentioned in Lewis's article, different types of doctors contribute differently. Such as maybe doctors who treat cold don't make big impact(because it's easy, with SOP), but who treat cancers well do. 2.How bad are bad doctors? 3.The value of "curing a disease", sometimes, curing a cancer doesn't mean you prevent a person dying from cancer, because he might get an... (read more)