Figure 1.
Structure of the hierarchical model of the ASRS constructed using bifactor analysis. In the original scale, 110 items load on five subscales respectively. In the bifactor analysis, all the items have loadings on both the general factor and one of the subscale specific factors.
Table 1.
Correlations between Different Sub-scales of ASRS.
Table 2.
Correlations between Items and ASRS Scales.
Table 3.
Model comparison between unidimensional, five-dimensional and bifactor models.
Figure 2.
The test information curve of the ASRS based on the bifactor analysis for the general stress factor. X-axis represents severity of the general factor (severity), which had been standardized (0 being average, 1 being a standard deviation). The Y-axis represents the test information value. Test information is a type of reliability criterion in IRT models, the larger the test information value, the less the measurement error and the better the reliability. In contrast to models constructed using CTT, in IRT models, there is a test information value corresponding to every severity point, representing the reliability at that level of severity. We obtained the test information curve by connecting all these values.
Table 4.
Correlations between CTT and Bifactor Analysis Results of ASRS.
Table 5.
Main results of bifactor analysis (M±SD).
Table 6.
Correlations between State/trait Anxiety and ASRS Results Under CTT and Bifactor Analysis.