Electronic Supplementary Material: Statistical Details of CFA and EFA

CFA and EFA using Polychoric Correlation Matrix

To assess for potential effect of non-normality of the ordinal scale analysis of CFA and EFA were repeated using polychoric correlation matrix. The same observations and model specifications were used in PROC CALIS and PROC FACTOR for CFA and EFA, respectively. Modeling results presented here strongly support the conclusions presented in the manuscript.

CFA

Factor loadings between each item and the subscale factors showed that 15 out 20 were above 0.80 and none were below 0.55. The inter-factor correlations between the 5 subscale factors were in the range of 0.77 – 0.97 with median at 0.87. Model fitting showed that RMSEA estimate 0.121; CFI 0.88; NFI 0.88; and NNFI 0.86. These numbers are close to the CFA results based on Pearson correlation in the main text, and none of the criteria is met according to the fit criteria.

EFA

The factorial pattern found in EFA is presented in the Supplemental table 4. A 4-factor structure explains 78% of the variance. Most factor loadings were above 0.6. The values and patterns of the factor loadings are very similar to what we found in the EFA based on Pearson correlation in the main text.

ESM Table 1. Comparison of CFA fit indices using whole cases versus using imputed data to assess for potential effect of item-nonresponse. CFA was performed using imputed data in which the missing items for 1934 respondents who answered any components of PACIC are imputed using the mean values.

Fit Summary / CFI using whole cases / CFI using mean score imputed data
Number of Observations / 1544 / 1934
RMSEA / 0.093 / 0.091
CFI / 0.909 / 0.908
NFI / 0.903 / 0.903
NNFI / 0.892 / 0.891

ESM Table 2. Additional analysis was performed in parallel to determine the number of factors to be included in EFA. Herein are shown the first 6 eigenvalues and the corresponding random data eigenvalues based on the mean and 95th percentile from the parallel analysis macro; 1000 datasets were generated with sample size 1544 and 20 variables. These results indicate that the first 4 factors have eigenvalues larger than the random data eigenvalues, such that 4 factors were chosen for EFA.

Eigenvalue / Random Data Eigenvalues
Mean / 95th Percentile
1 / 30.95 / 1.20 / 1.24
2 / 2.22 / 1.17 / 1.20
3 / 1.39 / 1.14 / 1.16
4 / 1.18 / 1.12 / 1.14
5 / 0.76 / 1.10 / 1.12
6 / 0.50 / 1.08 / 1.09

ESM Table 3. EFA factor loadings using imputed dataset with the PACIC four-factor structure identified de novo by EFA using Promax rotation. This analysis takes into account item-nonresponses by 1934 survey respondents. Values 0.4 are highlighted in bold font. F1: evaluation of services provided by the healthcare team. F2: personal goal setting and action plan. F3: Inclusion and collaboration with healthcare team. F4: help and support from social network.

PACIC Domains and items / EFA factors
F1 / F2 / F3 / F4
Patient Activation
1: Asked for my ideas when we made a treatment plan / 0.09 / 0.05 / 0.76 / 0.03
2: Given choices about treatment to think about / 0.02 / 0.05 / 0.86 / 0.04
3: Asked to talk about any problems with my medicines or their effects / 0.32 / 0.09 / 0.49 / -0.03
Delivery system design/Decision support
4: Given a written list of things I should do to improve my health / 0.03 / 0.60 / 0.10 / 0.11
5: Satisfied that my care was well organized / 0.45 / 0.25 / 0.17 / -0.13
6: Shown how what I did to take care of myself influenced my diabetes / 0.30 / 0.50 / 0.10 / -0.05
Goal setting/Tailoring
7: Asked to talk about my goals in caring for my diabetes / 0.16 / 0.59 / 0.19 / 0.00
8: Helped to set specific goals to improve my eating or exercise / 0.16 / 0.74 / -0.03 / 0.04
9: Given a copy of my treatment plan / 0.09 / 0.65 / 0.03 / 0.09
10: Encouraged to go to a specific group or class to help me cope with my diabetes / -0.07 / 0.13 / 0.02 / 0.77
11: Asked questions, either directly or on a survey, about my health habits / 0.43 / 0.20 / 0.10 / 0.12
Problem solving/Contextual
12: Sure that my doctor or nurse thought about my values, beliefs, and traditions when they recommended treatments to me / 0.76 / 0.00 / 0.07 / -0.03
13: Helped to make a treatment plan that I could carry out in my daily life. / 0.70 / 0.23 / -0.01 / -0.04
14: Helped to plan ahead so I could take care of my condition even in hard times / 0.70 / 0.11 / -0.02 / 0.07
15: Asked how my chronic condition affects my life / 0.67 / 0.05 / 0.08 / 0.11
Follow-up/Coordination
16: Contacted after a visit to see how things were going / 0.43 / 0.08 / 0.03 / 0.20
17: Encouraged to attend programs in the community that could help me / 0.12 / -0.11 / 0.01 / 0.83
18: Referred to a dietitian, health educator, or counselor / 0.10 / 0.26 / 0.00 / 0.45
19: Told how my visits with other types of doctors or other specialist, helped my treatment / 0.53 / 0.11 / 0.07 / 0.08
20: Asked how my visits with other doctors were going / 0.61 / 0.00 / 0.08 / 0.10

ESM Table 4. Factor loadings of the four-factor structure identified in EFA based on polychoric correlation using Promax rotation. Values 0.4 are highlighted in bold font. F1: evaluation of services provided by the healthcare team. F2: personal goal setting and action plan. F3: inclusion and collaboration with healthcare team. F4: help and support from social network.

PACIC Domains and items / EFA factors
F1 / F2 / F3 / F4
Patient Activation
1: Asked for my ideas when we made a treatment plan / 0.10 / 0.07 / 0.78 / 0.02
2: Given choices about treatment to think about / 0.03 / 0.05 / 0.88 / 0.05
3: Asked to talk about any problems with my medicines or their effects / 0.33 / 0.09 / 0.54 / -0.01
Delivery system design/Decision support
4: Given a written list of things I should do to improve my health / 0.04 / 0.66 / 0.11 / 0.11
5: Satisfied that my care was well organized / 0.5 / 0.29 / 0.20 / -0.17
6: Shown how what I did to take care of myself influenced my diabetes / 0.33 / 0.49 / 0.13 / -0.03
Goal setting/Tailoring
7: Asked to talk about my goals in caring for my diabetes / 0.21 / 0.57 / 0.21 / 0.02
8: Helped to set specific goals to improve my eating or exercise / 0.19 / 0.71 / 0.00 / 0.07
9: Given a copy of my treatment plan / 0.11 / 0.71 / 0.03 / 0.10
10: Encouraged to go to a specific group or class to help me cope with my diabetes / -0.09 / 0.17 / 0.02 / 0.82
11: Asked questions, either directly or on a survey, about my health habits / 0.46 / 0.20 / 0.11 / 0.14
Problem solving/Contextual
12: Sure that my doctor or nurse thought about my values, beliefs, and traditions when they recommended treatments to me / 0.82 / -0.01 / 0.08 / -0.02
13: Helped to make a treatment plan that I could carry out in my daily life. / 0.72 / 0.25 / -0.01 / -0.02
14: Helped to plan ahead so I could take care of my condition even in hard times / 0.74 / 0.14 / 0.00 / 0.08
15: Asked how my chronic condition affects my life / 0.69 / 0.07 / 0.09 / 0.12
Follow-up/Coordination
16: Contacted after a visit to see how things were going / 0.50 / 0.09 / 0.03 / 0.21
17: Encouraged to attend programs in the community that could help me / 0.15 / -0.13 / 0.02 / 0.89
18: Referred to a dietitian, health educator, or counselor / 0.09 / 0.29 / -0.01 / 0.50
19: Told how my visits with other types of doctors or other specialist, helped my treatment / 0.54 / 0.12 / 0.08 / 0.12
20: Asked how my visits with other doctors were going / 0.63 / 0.01 / 0.11 / 0.11