Table 1.

Slope Parameter Estimates and Standard Errors for the Bifactor and Unidimensional IRT Models

		Bifactor model										Unidimensional model
Item	Abbreviated content	a 1	SE	a 2	SE	a 3	SE	a 4	SE	a 5	SE	a	SE
8	feelings are strong	2.38	0.20	3.24	0.10	0.00	—	0.00	—	0.00	—	1.27	0.08
15	get into trouble … do w/o thinking	2.37	0.40	0.00	—	0.00	—	0.00	—	2.45	0.48	1.62	0.10
14	back and forth between feelings	2.00	0.12	0.21	0.09	0.00	—	0.00	—	0.00	—	1.90	0.11
19	upset, do things … aren’t good	1.98	0.13	0.00	—	0.00	—	0.00	—	0.33	0.09	1.95	0.13
17	when mad, can’t control what I do	1.96	0.13	0.55	0.11	0.00	—	0.00	—	0.00	—	1.95	0.13
21	get so mad, I can’t let all anger out	1.82	0.12	0.40	0.10	0.00	—	0.00	—	0.00	—	1.76	0.11
18	how I feel about myself changes	1.82	0.11	0.00	—	0.33	0.09	0.00	—	0.00	—	1.70	0.11
13	People … let me down	1.69	0.15	0.00	—	0.00	—	0.96	0.28	0.00	—	1.52	0.10
9	something important missing	1.65	0.10	0.00	—	0.10	0.09	0.00	—	0.00	—	1.60	0.10
7	do things without thinking	1.63	0.15	0.00	—	0.00	—	0.00	—	2.09	0.29	1.27	0.09
16	worry that people will leave …	1.56	0.10	0.00	—	0.58	0.10	0.00	—	0.00	—	1.49	0.10
10	friends … treated me badly	1.54	0.13	0.00	—	0.00	—	0.84	0.30	0.00	—	1.43	0.10
11	careless with things	1.43	0.11	0.00	—	0.00	—	0.00	—	0.40	0.09	1.45	0.10
20	friends and I are mean to each other	1.32	0.12	0.00	—	0.00	—	−0.16	0.21	0.00	—	1.28	0.09
2	feel very lonely	1.31	0.09	0.00	—	0.00	—	0.19	0.15	0.00	—	1.25	0.09
6	let people know … hurt me	1.15	0.12	0.00	—	0.00	—	0.90	0.35	0.00	—	1.06	0.08
3	upset when … parents/friends leave	1.01	0.13	0.00	—	2.78	0.17	0.00	—	0.00	—	0.61	0.07
4	do things … wild/out of control	0.96	0.08	0.00	—	0.00	—	0.00	—	0.74	0.09	1.00	0.08
12	change mind about what to do …	0.90	0.08	0.00	—	0.25	0.08	0.00	—	0.00	—	0.90	0.08
1 (r)	pretty happy person	0.83	0.08	−0.34	0.08	0.00	—	0.00	—	0.00	—	0.74	0.07
22 (r)	I get bored very easily	0.78	0.07	0.00	—	−0.04	0.08	0.00	—	0.00	—	0.81	0.07
24 (r)	once a friend, we stay friends	0.36	0.07	0.00	—	0.00	—	0.02	0.19	0.00	—	0.34	0.06
23 (r)	take good care of [my] things	0.27	0.07	0.00	—	0.00	—	0.00	—	0.26	0.08	0.27	0.06
5 (r)	feel … same way all the time	0.08	0.06	−0.06	0.08	0.00	—	0.00	—	0.00	—	0.05	0.06

Note. Boldface values indicate slope parameter values of .90 or higher. Dashes indicate that there are no standard errors for fixed parameters. IRT = item response theory; a = slope parameters; b = threshold parameters; SE = standard errors.