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Table 3 Corrected item-total correlations and internal consistency reliability if item was deleted for baseline scores of the interviewer and self-administered CRQ format

From: Self-administration and interviewer-administration of the German Chronic Respiratory Questionnaire: instrument development and assessment of validity and reliability in two randomised studies

Item CRQ-IA CRQ-SA
  Corrected item-total correlation Crohnbach alpha if item deleted Corrected item-total correlation Crohnbach alpha if item deleted
  Standardised dyspnoea domain Standardised dyspnoea domain
1 0.46 0.70 0.56 0.74
2 0.68 0.62 0.67 0.71
3 0.50 0.69 0.44 0.78
4 0.32 0.74 0.70 0.71
5 0.56 0.66 0.48 0.77
  Fatigue domain Fatigue domain
8 0.64 0.76 0.56 0.83
11 0.65 0.75 0.67 0.79
15 0.67 0.74 0.67 0.79
17 0.56 0.80 0.78 0.73
  Emotional function domain Emotional function domain
6 0.66 0.71 0.80 0.85
9 -0.03 0.86 0.37 0.92
12 0.72 0.70 0.67 0.87
14 0.41 0.76 0.65 0.88
16 0.84 0.67 0.79 0.86
18 0.56 0.74 0.74 0.87
20 0.57 0.73 0.85 0.85
  Mastery domain Mastery domain
7 0.49 0.75 0.67 0.83
10 0.65 0.66 0.76 0.80
13 0.44 0.78 0.65 0.85
19 0.72 0.63 0.77 0.79
  1. CRQ-IA = Interviewer administered Chronic Respiratory Questionnaire CRQ-SA = Self-administered Chronic Respiratory Questionnaire