> The majority of income differences comes from your skill. A doctor earn much more than a cashier due to having a more valuable skill, and that span makes up t

> The majority of income differences comes from your skill. A doctor earn much more than a cashier due to having a more valuable skill, and that span makes up the bulk of gini coefficient. Training certainly big plays a role, but the majority of a doctor's income, at least in the United States, comes from the fact that they're part of a labor cartel which artificially limits the number of doctors. No such cartel exists for cashiers. It's why even a mediocre doctor in the United States can make significantly more there than anywhere else in the world despite receiving equivalent training.