Most German states restrict universities from appointing their own staff to professorships. The higher education law of North Rhine-Westphalia, for example, says that academic staff of the university itself can be considered only in justified exceptional cases. The rule is called the Hausberufungsverbot, the ban on in-house appointments. A legal commentary in the journal Forschung & Lehre gives its purpose. It ensures that candidates’ qualifications are judged from outside, and it guards against academic patronage.