Table 3

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

DomainConstructNScore Respondents With Lowest Possible Score, %Respondents With Highest Possible Score, %Internal Consistency Test-Retest Reliabilitya ICCb (95% CI)Practice Mean Scores
MinMaxMean (SD)
Cronbach’s α, mean (min, max)Inter-Item Correlation, mean (max, min)Precision (standard error)Intra-Cluster Correlation Coefficient (95%CI)ReliabilityNumber of Responses Needed for 0.7 Reliability
Practice activation1,1329.0910083.69 (18.01)020.560.89 (0.86; 0.90)0.41 (0.39; 0.43)0.72 (0.55–0.83)c3.440.07 (0.03–0.11)c0.6631
Patient activation966010025.1 (30.8)47.05.580.800.670.55 (0.25–0.75)c6.570.022 (0.001–0.050)c0.33104
Experiences of safety problems1,171072.724.8 (9.4)63.1900.75 (0.71; 0.76)0.22 (0.20; 0.24)0.57 (0.37–0.72)1.830.02 (0.00–0.05)0.36109
Outcomes of patient safety (harm)Harm specific to the health domain1,05301004.7 (14.1) (0.95; 0.96)0.83 (0.82; 0.85)0.72 (0.55–0.83)c2.880.025 (0.001–0.053)c0.3890
Health care, personal care, and financial needs1,043091.662.4 (10.8)92.600.88 (0.78; 0.89)0.72 (0.63; 0.80)−0.02 (−0.29 to 0.26)2.230.019 (0.001–0.046)c0.31118
Time to recover from harm (type specific)15707524.7 (26.7)37.700.81 (0.71; 0.86)0.52 (0.45; 0.67)Not estimatedd13.590.057 (0.001–0.21)0.18309e
Time to recover from harm (overall)162010056.4 (41.6)27.632.27N/AN/ANot estimatedd19.500.17 (0.001–0.34)c0.4585e
Amount of harm experienced (overall)169010035.3 (26.3)3.00.60N/AN/ANot estimatedd13.570.000 (0.000–0.126)
Impact on overall health168010025.4 (32.5)54.27.74N/AN/ANot estimatedd15.550.11 (0.001–0.256)c0.32148e
General perceptions of patient safetyTrustworthiness1,133010087.5 (16.1)0.356.78N/AN/A0.26 (−0.02 to 0.50)c3.160.032 (0.002–0.061)c0.4571
Overall rating of patient safety1,139010086.0 (16.8)0.219.79N/AN/A0.24 (−0.03 to 0.48)c3.290.029 (0.001–0.058)c0.4378
  • N/A = not applicable (single item scales).

  • a Based on data from 64 patients who completed the questionnaire again after 2 weeks.

  • b One-way random effects intra-class correlation coefficients.

  • c P <.05.

  • d Not enough data to conduct the analyses (fewer than 10 of the respondents who completed the retest questionnaires reported harm experiences).

  • e Responses needed to have sufficient cases reporting harm.