Case studies of social value of work
In this article, we analyze common careers using the considerations from the article social value of work: how much the job helps customers, what the positive externalities of the job are, what the negative externalities of the job are, and how replaceable you'd be if you were to take the job.
Medicine
Benefit to customers — You can get a sense for how much social value doctors and nurses contribute by (i) considering how much you yourself have benefited from them and (ii) using the fact that doctors see ~1000 patients per year.
Positive externalities — By keeping people healthy, doctors and nurses reduce the amount of time people's families have to spend taking care of them, as well as the amount of time they can spend working and taking care of others.
Negative externalities — Doctors sometimes perform expensive, mostly unnecessary procedures, which health insurance companies have to pay for, which boosts the cost of health care for everyone.
Replaceability — There's no shortage of people who are willing to become doctors: over half of people who apply to medical school [| are rejected]. Unless you're significantly better at being a doctor than the strongest medical school rejects would be, you're replaceable, and the value that you contribute is the value of the work of your replacement rather than the immediate, direct value that you add as a doctor. For nurses, the situation is different: it's been [claimed| http://en.wikipedia.org/wiki/Nursing_shortage#United_States] that there will be a major need for additional nurses in the near future, suggesting that if you become a nurse, you wouldn't be replaceable, but others have questioned whether this is true.