Table 2 Scale reliability and structures
|  | Mean (SD) | Cronbach’s alpha | Number of items | Item-own scale correlation | Item-other scale correlation |
|---|---|---|---|---|---|
QLQ-C30 | Â | Â | Â | Â | Â |
Functional scales | Â | Â | Â | Â | Â |
Physical functioning | 71.16 (24.94) | .87 | 5 | 0.55–0.90 | 0.16–0.55 |
Role functioning | 69.74 (31.43) | .89 | 2 | 0.93–0.94 | 0.25–0.69 |
Emotional functioning | 71.51 (23.81) | .87 | 4 | 0.79–0.87 | 0.27–0.56 |
Cognitive functioning | 69.82 (25.80) | .60 | 2 | 0.77–0.87 | 0.23–0.55 |
Social functioning | 71.73 (30.72) | .85 | 2 | 0.90–0.94 | 0.28–0.50 |
Global quality of life | 54.19 (25.18) | .88 | 2 | 0.94–0.94 | 0.29–0.50 |
Symptom scales/items | Â | Â | Â | Â | Â |
Fatigue | 37.42 (23.04) | .77 | 3 | 0.76–0.87 | 0.27–0.62 |
Nausea and vomiting | 11.67 (17.53) | .64 | 2 | 0.66–0.94 | 0.19–0.38 |
Pain | 25.11 (26.93) | .81 | 2 | 0.89–0.91 | 0.26–0.55 |
Dyspnea | 20.37 (26.22) | Â | 1 | 1.00 | 0.30-0.51 |
Sleep disturbance | 25.08 (31.61) |  | 1 | 1.00 | 0.27–0.44 |
Appetite Loss | 16.94 (24.90) |  | 1 | 1.00 | 0.21–0.42 |
Constipation | 17.10 (25.78) |  | 1 | 1.00 | 0.14–0.25 |
Diarrhea | 12.46 (22.57) |  | 1 | 1.00 | 0.12–0.20 |
Financial difficulty | 31.38 (35.19) |  | 1 | 1.00 | 0.24–0.63 |
QLQ-BN20 scales | Â | Â | Â | Â | Â |
Future uncertainty | 34.38 (23.67) | .80 | 4 | 0.72–0.84 | 0.21–0.47 |
Visual disorder | 27.27 (28.22) | .83 | 3 | 0.73–0.90 | 0.19–0.36 |
Motor dysfunction | 29.14 (28.92) | .85 | 3 | 0.81–0.85 | 0.25–0.49 |
Communication deficit | 22.41 (27.82) | .90 | 3 | 0.84–0.92 | 0.18–0.50 |
QLQ-BN20 single items | Â | Â | Â | Â | Â |
Headache | 33.44 (31.07) |  | 1 | 1.00 | 0.30–0.41 |
Seizure | 9.84 (23.06) |  | 1 | 1.00 | 0.13–0.32 |
Drowsiness | 43.32 (28.03) |  | 1 | 1.00 | 0.26–0.42 |
Hair loss | 21.57 (31.01) |  | 1 | 1.00 | 0.00–0.26 |
Itchy skin | 16.61 (25.05) |  | 1 | 1.00 | 0.16–0.26 |
Weakness of legs | 35.42 (33.27) |  | 1 | 1.00 | 0.28–0.73 |
Bladder control | 21.39 (30.88) |  | 1 | 1.00 | 0.28–0.39 |