In the field I trained for, a PhD's median salary is only about 6% higher than someone with a master's. On the other hand, the spread of salaries for PhD's is

In the field I trained for, a PhD's median salary is only about 6% higher than someone with a master's. On the other hand, the spread of salaries for PhD's is much larger, mostly due to the amazingly unfounded assumption that a PhD somehow qualifies people for management positions.