This question was originally posted on Quora.com and was answered by Amy Chai, MD, Internal Medicine, MS Epidemiology Typically, some of the easiest fields are hardest to get into. For example, dermatology is very competetive, not because the specialty is challenging, but because it isn’t. Derm is a cakewalk with high pay and no real call. So people murder each other to get into derm so they can live easier professional lives. Therefore, it is “ultra hard” to get a residency spot. After that, no problem. For actual ultra hard, I would say neurosurgery or cardiothoracic surgery. Long hours, high risk procedures, arduous training make these surgical fields “ultra hard.” But even so, they are not intellectually any more challenging, but the procedures and stress are the challenging parts. For low pay, getting dumped on, and being forced to know everything, primary care is ultra hard. So ultra hard depends on your definition. Source
