Table 3

Causes of AEs (subcategories): proportions with preventable AEs and AEs leading to permanent disability (including death)

Causes of AEs			Frequency	Percentage (column %* within each main category)	Preventable AEs (row %*)	AEs with permanent disability row %*)
Technical		Design	0	0	0	0
		Construction	2	21	0	0
		Materials	10	34	100	0
		External	2	24	0	0
		Other	3	22	0	0
Human	Knowledge based	Knowledge	241	46	77	21
	Rule based	Qualifications	32	5	69	14
		Coordination	48	10	89	19
		Verification	105	21	83	18
		Intervention	84	26	74	19
		Monitoring	96	27	83	17
	Skill based	Slips	22	11	37	0
	Skill based	Tripping	5	3	75	0
		External	5	2	50	0
		Violation	126	29	81	17
		Other	45	14	40	5
Organisational		Protocols	32	22	92	33
		Transfer of knowledge	46	50	93	24
		Management priorities	7	17	100	0
		Culture	30	28	100	13
		External	6	5	100	0
		Other	4	4	100	0

AE, adverse event.
Reviewers could select more than one causal factor per AE. Preventability is related to the assessment of the preventability of the AE, not to the preventability of each cause underlying the AE.
↵* Percentages are weighted for oversampling of deceased patients and of patients admitted to a university hospital.