Skip to main content

Table 4 Traditional psychometrics scale-level results

From: Patient Uncertainty Questionnaire-Rheumatology (PUQ-R): development and validation of a new patient-reported outcome instrument for systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) in a mixed methods study

  Data quality Scaling assumptions Targeting Reliability Item convergent – discriminant validity: ITC range
  Missing data % Possible range (mid- point) Actual score range Mean (SD) CITC range Floor effect % Ceiling effect % Skewn. Cronbach’s alpha IIC mean 1 2 3 4 5
Symptoms & flares 7.52 14–56 (35) 14–56 35.29 (7.99) 0.44–0.69 0.72 0.72 −0.35 0.90 0.40 0.54–0.73 0.05–0.20 0.12–0.34 0.16–0.45 0.02–0.25
Medication 4.30 11–40 (27.50) 11–44 30.96 (6.77) −0.35–0.71 0.72 3.94 −0.15 0.90 0.60 0.02–0.18 0.46–0.77 0.23–0.40 0.25–0.33 0.04–0.43
Trust in doctor 2.15 8–32 (20) 8–32 22.37 (4.90) 0.40–0.71 0.72 1.43 −0.24 0.86 0.61 0.32–0.14 0.23–0.49 0.56–0.78 0.39–0.20 0.24–0.49
Self-management 3.58 6–24 (15) 6–24 18.80 (3.68) 0.53–0.67 0.72 8.60 −0.61 0.82 0.60 0.18–0.48 0.19–0.44 0.26–0.40 0.67–0.78 0.04–0.21
Impact 2.51 10–40 (25) 10–40 24.95 (8.15) 0.39–0.79 1.43 0.36 −0.13 0.93 0.73 0.00–0.24 0.11–0.42 0.20–0.43 0.04–0.29 0.49–0.84
  1. CITC corrected item total correlation, Skewn skewness statistic, IIC item-item correlation, ITC item total correlation