In German medicine, accepted good practice is written down in Leitlinien, clinical guidelines. Since 1995 the umbrella body of the medical scientific societies, the AWMF, has coordinated their development. Each guideline is graded by how it was made. An S1 guideline comes from an expert group in informal consensus. An S3 guideline has gone through every step of systematic development. Guidelines are not law, but in a given case they can define the care a doctor owes a patient. Even the method of writing a guideline is itself written down. The AWMF calls its rule book die Leitlinie zur Erstellung und Publikation of guidelines, the guideline for writing and publishing them.