TABLE 1—

Mean School Start Time by Adolescent and School Characteristics: National Comorbidity Survey—Adolescent Supplement, United States, 2001–2004

Variable	School Start Time, Mean (SE)	P
Individual characteristics
Age, y		.059
13	8:02 (2.57)
14	8:01 (2.98)
15	7:56 (2.43)
16	7:53 (2.97)
17	7:54 (2.61)
18	7:56 (4.13)
Sex		.843
Female	7:57 (2.10)
Male	7:57 (2.52)
Race		.941
Hispanic	7:56 (3.37)
Black	7:55 (4.22)
Other	7:57 (3.25)
White	7:57 (2.35)
Region		.437
Northeast	7:50 (5.08)
Midwest	7:57 (3.00)
South	8:01 (4.47)
West	7:55 (4.79)
Urbanicity		.022
Major metropolitan	7:54 (2.97)
Other urbanized	7:58 (4.15)
Nonurban	8:03 (1.41)
Income:poverty ratio		.445
< 1.5	7:58 (2.91)
≤ 3	7:58 (2.34)
≤ 6	7:57 (2.21)
> 6	7:56 (2.54)
Parental marital status		.115
Married or cohabitating	7:57 (2.27)
Previously married	8:00 (2.61)
Never married	7:59 (3.94)
Unknown	7:56 (2.61)
Parental education		.741
< high school	7:57 (2.68)
High school graduate	7:58 (2.47)
Some college	7:58 (2.55)
College graduate	7:56 (2.45)
No. of parents		.806
2	7:57 (2.23)
1 or other	7:57 (2.78)
No. of working parents		.864
0	7:56 (2.58)
1	7:57 (2.33)
2	7:57 (2.23)
Sibship size		.865
1	7:57 (2.57)
2	7:58 (2.33)
3	7:57 (2.20)
≥ 4	7:58 (2.50)
Extracurricular involvement		.766
Low	7:57 (2.56)
Moderate	7:57 (2.28)
High	7:58 (2.27)
Adolescent employment		.008
None	7:59 (2.28)
Current or previous	7:55 (2.52)
School characteristics
School level		.038
High school	7:54 (2.84)
Upper school	7:57 (3.37)
Middle school	8:04 (4.29)
Lower school	8:11 (4.87)
Kindergarten–12 school	7:51 (5.74)
School type		.155
Public	7:56 (2.54)
Public magnet or charter	7:56 (6.69)
Private	8:05 (3.46)

Note. Standard errors are in minutes. P values were determined by the Wald test.