TABLE 5—

Longitudinal Analysis of IRT Scale Scores for Mathematics and Reading, by Gender and Physical Education Category: Early Childhood Longitudinal Study, Kindergarten Class of 1998–1999

Gender, by Physical Education Categorya	Unadjusted,b B (95% CI)	Adjusted for Baseline and Kindergarten Program,c B (95% CI)	Adjusted for Baseline, Kindergarten Program, and Race/Ethnicity,d B (95% CI)	Adjusted for Baseline, Kindergarten Program, Race/Ethnicity, Family Income, and Mother’s Education,e B (95% CI)
Reading
Boys
Low (Ref)	. . .	. . .	. . .	. . .
Medium	0.6 (−1.9, 3.1)	0.5 (−1.3, 2.3)	0.0 (−1.6, 1.7)	0.2 (−1.6, 1.9)
High	0.7 (−1.8, 3.2)	−0.4 (−2.5, 1.6)	−0.3 (−2.2, 1.7)	−0.3 (−2.3, 1.7)
Girls
Low (Ref)	. . .	. . .	. . .	. . .
Medium	3.9 (1.7, 6.1)	2.1 (0.6, 3.6)	1.7 (0.3, 3.0)	1.1 (−0.2, 2.4)
High	3.2 (0.8, 5.6)	2.8 (1.2, 4.4)	2.4 (1.0, 3.9)	2.4 (1.0, 3.9)
Mathematics
Boys
Low (Ref)	. . .	. . .	. . .	. . .
Medium	0.7 (−1.4, 2.8)	0.2 (−1.2, 1.6)	−0.2 (−1.6, 1.1)	−0.2 (−1.5, 1.1)
High	1.3 (−0.8, 3.4)	0.3 (−1.2, 1.7)	0.3 (−1.1, 1.8)	0.4 (−1.0, 1.8)
Girls
Low (Ref)	. . .	. . .	. . .	. . .
Medium	2.9 (0.8, 5.0)	1.2 (−0.1, 2.5)	1.0 (−0.2, 2.1)	0.7 (−0.4, 1.8)
High	2.1 (−0.3, 4.5)	1.7 (0.3, 3.1)	1.5 (0.1, 2.8)	1.5 (0.4, 2.7)

Note. IRT = item response theory; CI = confidence interval.

^aMinutes per week of physical education was estimated by multiplying the median frequency by the median duration of time reported by teachers for physical education and then categorized by minutes per week as low (0–35), medium (36–69), or high (70–300).

^bModel contained 2 independent variables: physical education category and grade level.

^cModel added a baseline IRT scale score (with a grade-level interaction term), an indicator for time from baseline assessment, and a variable to indicate whether a student attended school for half a day (i.e., half–day kindergarteners).

^dModel added race/ethnicity with a grade-level interaction term.

^eModel added family income and mother’s education with a grade-level interaction term.