Table 3.

Distribution of Scores and Reliability of the Patient Reported Experiences and Outcomes of Safety in Primary Care (PREOS-PC) Scales

Domain	Construct	N	Score			Respondents With Lowest Possible Score, %	Respondents With Highest Possible Score, %	Internal Consistency		Test-Retest Reliabilitya ICCb (95% CI)	Practice Mean Scores
			Min	Max	Mean (SD)
								Cronbach’s α, mean (min, max)	Inter-Item Correlation, mean (max, min)		Precision (standard error)	Intra-Cluster Correlation Coefficient (95%CI)	Reliability	Number of Responses Needed for 0.7 Reliability
Practice activation		1,132	9.09	100	83.69 (18.01)	0	20.56	0.89 (0.86; 0.90)	0.41 (0.39; 0.43)	0.72 (0.55–0.83)c	3.44	0.07 (0.03–0.11)c	0.66	31
Patient activation		966	0	100	25.1 (30.8)	47.0	5.58	0.80	0.67	0.55 (0.25–0.75)c	6.57	0.022 (0.001–0.050)c	0.33	104
Experiences of safety problems		1,171	0	72.72	4.8 (9.4)	63.19	0	0.75 (0.71; 0.76)	0.22 (0.20; 0.24)	0.57 (0.37–0.72)	1.83	0.02 (0.00–0.05)	0.36	109
Outcomes of patient safety (harm)	Harm specific to the health domain	1,053	0	100	4.7 (14.1)	81.8	0.29	0.96 (0.95; 0.96)	0.83 (0.82; 0.85)	0.72 (0.55–0.83)c	2.88	0.025 (0.001–0.053)c	0.38	90
	Health care, personal care, and financial needs	1,043	0	91.66	2.4 (10.8)	92.6	0	0.88 (0.78; 0.89)	0.72 (0.63; 0.80)	−0.02 (−0.29 to 0.26)	2.23	0.019 (0.001–0.046)c	0.31	118
	Time to recover from harm (type specific)	157	0	75	24.7 (26.7)	37.7	0	0.81 (0.71; 0.86)	0.52 (0.45; 0.67)	Not estimatedd	13.59	0.057 (0.001–0.21)	0.18	309e
	Time to recover from harm (overall)	162	0	100	56.4 (41.6)	27.6	32.27	N/A	N/A	Not estimatedd	19.50	0.17 (0.001–0.34)c	0.45	85e
	Amount of harm experienced (overall)	169	0	100	35.3 (26.3)	3.0	0.60	N/A	N/A	Not estimatedd	13.57	0.000 (0.000–0.126)	–	–
	Impact on overall health	168	0	100	25.4 (32.5)	54.2	7.74	N/A	N/A	Not estimatedd	15.55	0.11 (0.001–0.256)c	0.32	148e
General perceptions of patient safety	Trustworthiness	1,133	0	100	87.5 (16.1)	0.3	56.78	N/A	N/A	0.26 (−0.02 to 0.50)c	3.16	0.032 (0.002–0.061)c	0.45	71
	Overall rating of patient safety	1,139	0	100	86.0 (16.8)	0.2	19.79	N/A	N/A	0.24 (−0.03 to 0.48)c	3.29	0.029 (0.001–0.058)c	0.43	78

N/A = not applicable (single item scales).

^aBased on data from 64 patients who completed the questionnaire again after 2 weeks.

^bOne-way random effects intra-class correlation coefficients.

^cP <.05.

^dNot enough data to conduct the analyses (fewer than 10 of the respondents who completed the retest questionnaires reported harm experiences).

^eResponses needed to have sufficient cases reporting harm.