Table 3 Patient questionnaire subscales with mean scores and reliability estimates (Cronbach’s alpha)
Subscale | No. of items | Score range (min–max) | Pilot study | Final study | ||
|---|---|---|---|---|---|---|
Mean (SD) | Cronbach’s alpha | Mean (SD) | Cronbach’s alpha | |||
Motivation | 9 | (9–36) | 34.70 (2.52) | 0.85 | 34.20 (3.88) | 0.92 |
Risks | 5 | (5–20) | 19.09 (2.10) | 0.85 | 18.73 (2.49) | 0.83 |
Understanding trial purpose | 3 | (3–12) | 11.81 (0.62) | 0.67 | 11.49 (1.45) | 0.83 |
Benefits | 3 | (3–12) | 11.68 (0.78) | 0.78 | 11.40 (1.53) | 0.85 |
Cost and convenience | 4 | (4–16) | 13.98 (2.07) | 0.62 | 13.58 (2.87) | 0.78 |
Contribution to health | 3 | (3–12) | 11.38 (1.04) | 0.67 | 11.60 (1.38) | 0.96 |
Total number of items | 27 | |||||