Table 2

Mean interitem correlation for items within a subscale and between items outside of the investigated subscale.

ScaleMean r
(within subscale)
Mean r
(outside subscale)
Adjusted mean difference 95% CIP valueCronbach’s alpha
App:
SRI-RC
0.3190.19−9.9 (−19.5 to 0.43)0.040.79
Paper:
SRI-RC
0.2150.1520.69
App:
SRI-PF
0.1750.154.67 (−6.6 to 15.9)0.410.56
Paper:
SRI-PF
0.4380.1540.83
App:
SRI-AS
0.1910.181−6.8 (−15.8 to 2.2)0.140.63
Paper:
SRI-AS
0.1440.0590.54
App:
SRI-SR
0.2740.152−1.4 (−10.3 to 7.6)0.760.7
Paper:
SRI-SR
0.2610.1340.63
App:
SRI-AX
0.470.1944 (−8.5 to 16.6)0.530.81
Paper:
SRI-AX
0.2630.1280.64
App:
SRI-WB
0.2840.205−0.5 (−9.9 to 8.9)0.920.78
Paper:
SRI-WB
0.2040.150.7
App:
SRI-SF
0.2330.2015.1 (−4.4 to 14.6)0.290.7
Paper:
SRI-SF
0.1850.1430.63
  • r, correlation coefficient; SRI, Severe Respiratory Insufficiency Questionnaire; SRI-AS, SRI subscale “attendant symptoms and sleep”; SRI-AX, SRI subscale “anxiety”; SRI-PF, SRI subscale “pulmonary functioning”; SRI-RC, SRI subscale “respiratory complaints; SRI-SF, SRI subscale “social functioning”; SRI-SR, SRI subscale “social relationships”; SRI-WB, SRI subscale “psychological well-being”.