Table 1. Demographic characteristics of the MTwiNS and ABC Brains samples.

	MTwiNS				ABC Brains
Measure	n	M or Median	SD	Range	n	M or Median	SD	Range
Age (Months)	464	175.60	25.68	87–237	27	122.77	10.96	100–141
Age (years)	464	14.63	2.14	7.25–19.75	27	10.23	0.91	8.33–11.75
Pubertal Developmenta	464	2.96	0.80	1.17–4	27	1.73	0.57	1–3
Annual Household Incomeb	464	$80,000 to $89,999		$4,999 or less–$90,000 or more	27	$20,000 to $24,999		Under $5,000 –Greater than $75,000
Income-to-Needs Ratioc	464	2.40	0.92	0.09–3.72	27	1.18	0.92	0.08–3.05

^aPubertal development was measured via parent report with the Pubertal Development Scale [38]. Higher scores on the Pubertal Development Scale indicate later pubertal development, where 1 = “not yet started,” 2 = “barely started,” 3 = “definitely started,” and 4 = “seems complete”.

^bAnnual household income is parent report annual gross household income.

^cIncome-to-needs ratio was calculated by dividing the mid-point of each family’s income bracket by a poverty threshold based on interview year and number of people living in the household.