EPSO primarily organises open selection procedures for all EU citizens. No distinction is made between internal and external candidates and the tests, including computer-based tests and written tests, are marked anonymously.

All candidates undergo equivalent tests and the same eligibility criteria apply to all.

The Staff Regulations (the official document describing the rules, principles and working conditions of the European civil service) define a very clear legal framework for organising competitions. Open competitions are for all EU citizens while internal competitions are organised exclusively for candidates already working in the Institutions. No additional credit may be given to internal candidates in open competitions, as this would clearly constitute unequal treatment.