Table 9.

Correlations Between 2PL IRT and Congeneric Fits, Data From Congeneric Model.

	Correlation in discrimination parameter			Correlation in difficulty parameter			Correlation in factor scores
Congeneric data vs. 2PL fit	Minimum	Median	Maximum	Minimum	Median	Maximum	Minimum	Median	Maximum
Case 1	0.892	0.963	0.991	0.962	0.989	0.998	0.999	0.999	1.000
Case 2	0.899	0.97	0.991	0.976	0.992	0.997	0.999	0.999	1.000
Case 3	0.903	0.966	0.983	0.966	0.991	0.995	0.999	1.000	1.000
Case 4	0.906	0.966	0.986	0.982	0.991	0.995	0.999	1.000	1.000
Case 5	0.901	0.963	0.986	0.968	0.988	0.996	0.999	1.000	1.000
Case 6	0.918	0.967	0.984	0.985	0.991	0.995	0.999	1.000	1.000

Note. 2PL IRT = two-parameter logistic item response theory.