TABLE 3.

HLM Results for 3-Level Model Examining the Effect of SWPBIS on Concentration Problems

Concentration Problemsa	Coefficient	SE	t Ratio	P Value
Intercept
Intercept	2.2616	0.0347	65.22	<.001
School-level variables
Mobility	−0.0005	0.0030	−0.16	NS
Student/teacher ratio	0.0190	0.0107	1.77	NS
Faculty turnover	−0.0021	0.0031	−0.67	NS
Enrollment	0.0141	0.0182	0.77	NS
Student-level variables
Special education status	0.7057	0.0422	16.72	<.001
Ethnicity (black)	0.2221	0.0430	5.17	<.001
Grade cohort	−0.1818	0.0559	−3.26	<.01
FARMS	0.3048	0.0266	11.47	<.001
Gender	0.4262	0.0178	23.96	<.001
Slope (growth)
Intercept	−0.0036	0.0126	−0.29	NS
School-level variables
SWPBIS intervention	−0.0254	0.0122	−2.08	<.05
Mobility	0.0022	0.0009	2.51	<.05
Student/teacher ratio	−0.0066	0.0029	−2.28	<.05
Faculty turnover	0.0026	0.0010	2.48	<.05
Enrollment	−0.0107	0.0047	−2.28	<.05
Student-level variables
Special education status	−0.0204	0.0093	−2.18	<.05
Ethnicity (black)	0.0352	0.0117	3.01	<.001
Grade cohort	0.0449	0.0195	2.30	NS
FARMS	0.0197	0.0076	2.60	NS
Gender	0.0367	0.0078	4.69	<.01
Post hoc cross-level interactions
Grade cohort × SWPBIS	−0.0396	0.0300	−1.32	NS
Gender × SWPBIS	0.0153	0.0122	1.26	NS
Special education status × SWPIS	0.0199	0.0165	1.21	NS
Random Effect	Variance Component	χ2		P Value
Level 1	0.5597
Level 2	0.6692	51851.3		<.001
Level 3 time/slope	0.0017	104.6		<.001

Akaike information criterion = 100306.4; Bayesian information criterion = 100208.0. SWPBIS was coded 1 (intervention), 0 (comparison). FARMS indicates free or reduced-price meals status. Gender was coded 1 (male), 0 (female). Ethnicity was coded 1 (black), 0 (all others). Grade cohort indicates the grade the youth was in when the trial began, coded 1 (kindergarten), 0 (grades 1 or 2).

^aResults presented are from the model that did not include the post hoc interactions. The interclass correlation for concentration problems was 0.02.