Hello, the undergraduate education of public security university is four years: three years for master and three years for doctor. As far as I know, none of the remaining doctoral students in public security university studied under this master's degree ~ they are not stupid. Their salary was very high a few years ago. They go to graduate school and study for a doctor, unless they are out of their minds ~ As you said, if a doctor of public security studies for a doctor, he enjoys official treatment, and his salary is 3000+ a month in Beijing, because Beijing implements the system of 3, 5, 8, 1.