Table 5 Inter-item correlations between ASD item-level scores and alpha scores for internal consistency
From: Development and evaluation of the Acromegaly Symptom Diary
Timepoint/ASD Item | Inter-item Correlation | ||||||||
|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | |
Baseline (n = 20–31) | |||||||||
Item 1. Headache pain | NA | NA | NA | NA | NA | NA | NA | NA | NA |
Item 2. Joint pain | 0.62 | NA | NA | NA | NA | NA | NA | NA | NA |
Item 3. Sweating | 0.42 | 0.73 | NA | NA | NA | NA | NA | NA | NA |
Item 4. Fatigue | 0.82 | 0.77 | 0.55 | NA | NA | NA | NA | NA | NA |
Item 5. Leg weakness | 0.59 | 0.68 | 0.40 | 0.70 | NA | NA | NA | NA | NA |
Item 6. Swelling | 0.54 | 0.72 | 0.37 | 0.52 | 0.59 | NA | NA | NA | NA |
Item 7. Numbness/tingling | 0.52 | 0.83 | 0.46 | 0.69 | 0.56 | 0.64 | NA | NA | NA |
Item 8. Sleep difficulty | 0.67 | 0.72 | 0.65 | 0.79 | 0.69 | 0.44 | 0.61 | NA | NA |
Item 9. Short-Term Memory | 0.59 | 0.76 | 0.55 | 0.71 | 0.89 | 0.68 | 0.69 | 0.69 | NA |
Coefficient alpha without column item | 0.93 | 0.92 | 0.93 | 0.93 | 0.92 | 0.94 | 0.93 | 0.93 | 0.92 |
Coefficient alpha (all items) | 0.94 | NA | NA | NA | NA | NA | NA | NA | NA |
Coefficient alpha without column item (only Items 1–7) | 0.90 | 0.87 | 0.92 | 0.88 | 0.89 | 0.90 | 0.89 | NA | NA |
Coefficient alpha (only Items 1–7) | 0.91 | NA | NA | NA | NA | NA | NA | NA | NA |
Week 17 (n = 17–27) | |||||||||
Item 1. Headache pain | NA | NA | NA | NA | NA | NA | NA | NA | NA |
Item 2. Joint pain | 0.16 | NA | NA | NA | NA | NA | NA | NA | NA |
Item 3. Sweating | 0.31 | 0.37 | NA | NA | NA | NA | NA | NA | NA |
Item 4. Fatigue | 0.55 | 0.36 | 0.34 | NA | NA | NA | NA | NA | NA |
Item 5. Leg weakness | 0.35 | 0.56 | 0.18 | 0.72 | NA | NA | NA | NA | NA |
Item 6. Swelling | 0.17 | 0.58 | 0.28 | 0.17 | 0.23 | NA | NA | NA | NA |
Item 7. Numbness/tingling | −0.10 | 0.62 | 0.49 | 0.47 | 0.38 | 0.57 | NA | NA | NA |
Item 8. Sleep difficulty | 0.18 | 0.63 | 0.47 | 0.55 | 0.70 | 0.28 | 0.53 | NA | NA |
Item 9. Short-term memory | −0.26 | 0.45 | 0.17 | 0.31 | 0.56 | 0.59 | 0.74 | 0.69 | NA |
Coefficient alpha without column item | 0.88 | 0.83 | 0.86 | 0.84 | 0.80 | 0.85 | 0.83 | 0.79 | 0.83 |
Coefficient alpha (all items) | 0.85 | NA | NA | NA | NA | NA | NA | NA | NA |
Coefficient alpha without column item (only Items 1–7) | 0.81 | 0.75 | 0.79 | 0.76 | 0.76 | 0.79 | 0.77 | NA | NA |
Coefficient alpha (only Items 1–7) | 0.80 | NA | NA | NA | NA | NA | NA | NA | NA |