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. Author manuscript; available in PMC: 2018 Nov 1.
Published in final edited form as: Qual Life Res. 2017 Jul 5;26(11):2973–2985. doi: 10.1007/s11136-017-1640-3

Table 2.

Confirmatory Factor Analysis and Measurement Invariance Testing Results.

Domain Name /
CFA Model		 χ2 df RMSEA CFI TLI WRMR χ2 Test of Invariance ΔCFI Pass/
Fail
Pain Interference
  Phone Mode 18.927 2 0.145 0.999 0.997 0.521 --- --- ---
  PC Mode 4.329 2 0.054 1 1 0.210 --- --- ---
  Configural 69.574 15 0.095 0.999 0.998 0.673 --- --- Fail
Fatigue
  Phone Mode 10.863 2 0.105 0.999 0.998 0.427 --- --- ---
  PC Mode 1.158 2 0 1 1 0.137 --- --- ---
  Configural 34.530 15 0.057 0.999 0.999 0.489 --- --- Pass
  Strong 58.849 33 0.044 0.999 0.999 0.717 p = 0.274 0 Pass
Depression
  Phone Mode 20.001 2 0.150 0.998 0.994 0.626 --- --- ---
  PC Mode 1.852 2 0.010 1 1 0.180 --- --- ---
  Configural 33.150 15 0.055 0.999 0.999 0.467 --- --- Pass
  Strong 53.474 32 0.041 0.999 0.999 0.670 p = 0.403 0 Pass
Anxiety
  Phone Mode 1.168 2 0 1 1.001 0.142 --- --- ---
  PC Mode 0.545 2 0 1 1 0.101 --- --- ---
  Configural 22.703 15 0.036 0.999 0.999 0.394 --- --- Pass
  Strong 56.253 29 0.048 0.997 0.998 0.812 p = 0.041 −0.0018 Pass
Sleep Disturbance1
  Phone Mode 0.327 1 0 1 1.001 0.063 --- --- ---
  PC Mode 1.702 1 0.042 1 0.999 0.091 --- --- ---
  Configural 26.734 13 0.051 0.999 0.997 0.374 --- --- Pass
  Strong 84.412 31 0.066 0.995 0.996 0.876 p < 0.001* −0.004 Fail
  Partial Strong 40.321 26 0.037 0.999 0.999 0.568 p = 0.325 0 Pass
Sleep Related Impairment2
  Phone Mode 47.759 19 0.062 0.996 0.995 0.610 --- --- ---
  PC Mode 59.371 19 0.073 0.998 0.997 0.621 --- --- ---
  Configural 271.911 93 0.069 0.993 0.991 0.951 --- --- Pass
  Strong 396.807 131 0.071 0.990 0.991 1.376 p < 0.001* −0.003 Fail
  Partial Strong 284.918 126 0.056 0.994 0.994 1.092 p = 0.513 0.001 Pass
Diarrhea3
  Phone Mode 11.610 6 0.048 1 0.999 0.335 --- --- ---
  PC Mode 9.694 6 0.039 1 1 0.296 --- --- ---
  Configural 147.330 41 0.080 0.996 0.993 0.903 --- --- Pass
  Strong 170.112 68 0.061 0.996 0.996 1 p = 0.713 0 Pass
Bowel Incontinence
  Phone Mode 4.154 2 0.052 1 0.999 0.281 --- --- ---
  PC Mode 6.001 2 0.071 1 0.999 0.341 --- --- ---
  Configural 25.389 16 0.038 0.999 0.999 0.471 --- --- Pass
  Strong 32.141 32 0.003 1 1 0.526 p = 0.881 0.001 Pass
Physical Function
  Phone Mode 1.861 2 0 1 1 0.140 --- --- ---
  PC Mode 0.854 2 0 1 1 0.109 --- --- ---
  Configural 9.988 15 0 1 1.001 0.195 --- --- Pass
  Strong 29.871 33 0 1 1 0.392 p = 0.773 0 Pass
Illness Impact – Negative4
  Phone Mode 56.466 18 0.073 0.994 0.990 0.596 --- --- ---
  PC Mode 52.987 18 0.070 0.997 0.996 0.568 --- --- ---
  Configural 196.618 91 0.054 0.994 0.993 0.737 --- --- Pass
  Strong 229.245 129 0.044 0.995 0.995 0.933 p = 0.593 0 Pass
Illness Impact – Positive5
  Phone Mode 20.893 8 0.063 0.998 0.992 0.304 --- --- ---
  PC Mode 16.456 8 0.051 0.998 0.995 0.280 --- --- ---
  Configural 186.692 71 0.064 0.989 0.981 0.729 --- --- Pass
  Strong 314.963 109 0.069 0.980 0.978 1.183 p < 0.001* −0.009 Fail
  Partial Strong 217.044 104 0.052 0.989 0.987 0.914 p = 0.275 0 Pass
Interest in Sexual Activity
  Phone Mode 3.002 2 0.035 1 1 0.201 --- --- ---
  PC Mode 15.065 2 0.128 0.999 0.997 0.447 --- --- ---
  Configural 94.260 15 0.115 0.996 0.993 0.761 --- --- Fail
Erectile Function
  Configural 10.580 5 0.068 1 0.999 0.271 --- --- Pass
  Strong 84.730 17 0.128 0.995 0.996 0.996 p = < 0.001* −0.005 Fail
  Partial Strong 18.272 12 0.046 1 0.999 0.405 p = 0.423 0 Pass
Global Satisfaction with Sex Life6
  Phone Mode 1.961 1 0.064 1 0.999 0.137 --- --- ---
  PC Mode 14.212 1 0.234 0.999 0.993 0.358 --- --- ---
  Configural 37.278 13 0.093 0.998 0.996 0.436 --- --- Fail
Notes:
  • χ2 = scaled chi-square test of model fit.
  • df = scaled degrees of freedom for the scaled chi-square statistic.
  • RMSEA = scaled root mean square error of approximation.
  • CFI = scaled comparative fit index.
  • TLI = scaled Tucker-Lewis index.
  • WRMR = weighted root mean square residuals.
  • χ2 Test of Invariance = scaled chi-square difference test comparing the strong (or partial strong) invariance model to the configural invariance model. Significant p values were marked with an asterisk after a Bonferroni correction (α = 0.05/50 = 0.001).
  • ΔCFI = CFIstrong − CFIconfigural (or CFIpartial.strong − CFIconfigural)
  • Model modifications (with possible explanations) applied toward both survey modes prior to invariance testing:
    1. Sleep Disturbance: freely estimated the residual covariance between SLEEP20 and SLEEP44 (both were worded similarly asking about problems with sleep).
    2. Sleep Related Impairment: freely estimated the residual covariance between SLEEP6 and SLEEP7 (both assessed sleepiness during the day).
    3. Diarrhea: freely estimated the residual covariances among GISX38, GISX40, and GISX41 (all related to “having loose or watery stools”).
    4. Illness Impact – Negative: freely estimated the residual covariance between II58.a and II59.a (both assessed social disconnectedness), and between II71.a and II80.a (both assessed uneasiness).
    5. Illness Impact – Positive: freely estimated the residual covariances among II7.a, II32.a, and II35.a (all assessed optimism), and among the other five items (all related to more profound understandings of life).
    6. Global Satisfaction with Sex Life: freely estimated the residual covariance between SFSAT101 and SFSAT102 (both used the phrase “sex life”).
  • For Bowel Incontinence domain, the autocorrelation of GISX46 over time was not estimated due to model convergence issues.