Table 1 Data sources that were screened in this study

(1) PhD regulations (for every different type of PhD awarded by the medical faculty)

(2) Habilitation regulations (habilitation is an academic degree which is awarded after the PhD, and which involves a second, larger research thesis and additional teaching; it historically was and often still is considered a prerequisite for obtaining tenure or securing third-party funding in Germany [74, 75])

(3) Application forms for tenured professorships

(4) Procedural guidelines for the tenure process (Berufungsordnungen)

(5) Websites of clinical research units

(6) Animal research websites, including for animal facilities, 3R centres and animal protection offices

(7) General research websites of the medical faculties or university hospitals