Analysis | Item residual | Person residual | (Cond.)a Chi-Squareb | PSIc | Alpha | Unidimensionalityd |
|---|
Mean | SD | Mean | SD | Value (df) | p |  |  | % tests > 5% | 95% CI |
|---|
1) 12-item scale | 0.05 | 2.19 | −0.31 | 1.33 | 138.46 (48) | 0.000 | 0.86 | 0.87 | 23.0 | 5–9.9 |
2) 2 super-items | 0.15 | 0.88 | −0.59 | 1.01 | 29.24 (22) | 0.138 | 0.85 | 0.86 | 4.2 | 1.8–6.6 |
Ideal values | 0.00 | 1.00 | 0.00 | 1.00 |  | > 0.01* | > 0.70 | > 0.70 | < 5.0 | LCI < 5 |
- Abbreviations: T1/2 testlet, or super-item 1/2, Cond. conditional, df degrees of freedom, PSI person separation index, Alpha Cronbach’s alpha, SD standard deviation, CI confidence interval, LCI lower bound of the 95% CI
- aConditional Chi-Square: only applicable for the super-item solution; for the item-based solution, the Chi Square is shown
- bChi-Square of T1: 3392 (4), p = 0,494; Chi-Square of T2: 1054 (4), p = 0,901. Perfect values are > 0.004* (Bonferroni adjusted)
- cThe PSI indicates the reliability and differentiation of strata
- dBased on independent t-tests to compare person residuals which are positively and negatively loading on the first principal component
- *Bonferroni adjusted and variable with number of items
