Scientists undergo various qualification phases. Four career phases are described in the Framework for Research Careers of the European Commission. In the PhD phase - First Stage Researcher (R1) - the focus is on the aptitude for scientific work. The ensuing early and advanced PostDoc phase - Recognized Researcher (R2) and Established Researcher (R3) - serves to expand scientific expertise and demonstrate scientific excellence. Qualification phases R1 to R3 include junior scientists. Leading researchers, who have already provided independent scientific work in their area of expertise and perform key functions, are in the process of establishing and consolidating their position - Leading Researcher (R4).
The classification of the qualification phases is based on the degree of scientific independence, the reputation, the performance in research and teaching and the expression of the professional, interdisciplinary and social competence profile.