Exclusion reason	Number of excluded criteria	Proportion of all excluded criteria (n = 329) in %
Too broad (e.g., not clear how to measure the fulfillment of criteria objectively)	113	34.35
Too specific (e.g., for a specific treatment center or diagnosis)	75	22.8
Does not measure the quality of care or at least not at only an individual center	59	17.93
Covered by good clinical practice	17	5.17
Covered by clinical trial participation or treatment protocols	29	8.81
Regulated nationally	23	6.99
Related to the certification of professionals or specialties	8	2.43
Given by MDT (e.g., “In case of a necessary interim consultation about a patient an extra meeting of the MDT with all its members should be arranged within one working day).” (Knops et al., 2012)	3	0.91
Not an outcome of the study (e.g., “rates of chemotherapy errors” (McCavit & Winick, 2012) mentioned in the discussion of an article but not in the results or major topic of this article)	2	0.61
Total	329	100