Table 1.

Absolute Standardized Mean Difference (SMD) Before and After Balance Check

	Sport SMD		Performance arts or clubs SMD
Covariates	Before	After	Before	After
Panel I: (Sort by correlation with academic belief)
Teacher-student warmth_s	.201	.052	.021	.001
Subjective valuing of reading achievement_s	.264	.108	.165	.169
Subjective overall value of academic achievement_s	.298	.084	.197	.215
Educational aspirations for student_p	.156	.143	.402	.195
Student’s hyperactivity_p	.057	.142	.135	.078
School belonging_s	.307	.108	.019	.031
Overall academic competence_s	.352	.090	.168	.158
Reading competence beliefs_s	.246	.098	.155	.121
Student’s conduct problems_p	.101	.196	.225	.126
Student’s ethnicity (African American vs White)	.093	.053	.037	.017
Panel II: (Sort by correlation with academic achievement)
Highest adult educational level in household_p	.422	.251	.426	.139
Educational aspirations for student_t	.198	.158	.151	.008
Classroom engagement_t	.18	.154	.143	.056
Educational aspirations for student_p	.156	.143	.402	.195
Student’s economic disadvantaged status	.211	.138	.324	.101
Student’s hyperactivity_t	.077	.135	.204	.106
Student’s conduct problems_p	.101	.196	.225	.126
School level reading achievement score Time 8	.049	.168	.116	.013
Woodcock-Johnson III Broad Math W Score	.217	.149	.366	.246
School level math achievement score at Time 8	.026	.159	.129	.008
Panel III: (Sort by correlation with friend engagement)
Student’s economic disadvantaged status	.211	.138	.324	.101
School level reading achievement score Time 8	.049	.168	.116	.013
School level math achievement score at Time 8	.026	.159	.129	.008
Highest adult educational level in household_p	.422	.251	.426	.139
Student’s gender	.277	.172	.257	.060
Student’s ethnicity (Hispanic vs. White)	.283	.117	.207	.090
Classroom engagement_t	.180	.154	.143	.056
Teacher-student warmth	.201	.052	.021	.001
Home school relationship (alliance)	.174	.141	.076	.042
Friends’ prosocial norms	.372	.184	.040	.047