slmkhoo:That's very fine distinctions! It sounds like it's going against the trend now? Is the difference only because of the class of degree or are there any other differences in experience, other skills etc between the 3?
All 3 are fresh graduates and have done internship with the organisation. The civil service tends to give a starting salary based on the class of degree, not by skills and job experience.
It is very important to do internships during undergrad years. My daughter and most of her friends received job offers from the organisations that they had interned with, a year before they graduate.

