Variable	Description
Maternal Demographic Status
Region of residence	NCES-provided sampling frame region markers (27% south, 2% northeast, 7% midwest, 64% west).
Location of residence	Following the lead of Lee and Burkham (2002), the original NCES-provided categories of urbanicity were collapsed into a set of three dummy variables (4% small town/rural, 29% city fringe/large town, 67% central city).
Number of children	At various points, NCES completed household rosters, which provided information on who was living in the home with the target child. The fall kindergarten roster gave the number of other children (besides the target child) living with the mother (M = 2.89, SD = 1.25).
Maternal age	In 1998, mothers gave their ages (M = 31.88, SD = 6.03).
Age at first birth	In 1998, mothers reported how old they were when they had their first child (M = 21.75, SD = 4.32).
Non-marital birth	Mothers’ 1998 reports of the date of the target child’s birth and the length of any marriage to the child’s father were compared to identify target children born outside of wedlock (24%).
Maternal Characteristics
Employment status	As described in the methods section, maternal reports on paid labor were collapsed into markers of full-time (26+ hours of paid labor per week) and part-time (1–25 hours) employment (26% and 12% respectively).
Work history	In 1998, mothers reported whether (1 = yes, 0 = no) they had been employed for pay outside the home between the target child’s birth and start of kindergarten (39%).
Public assistance status	In 1998, mothers reported whether they had received AFDC/TANF in the past year (10%).
General health	In 1999, mothers assessed their own physical health on a scale from 1 (poor) to 5 (excellent) (M = 3.34, SD = 1.01).
Depressive symptomatology	ECLS-K included a condensed version of the Center for Epidemiologic Studies-Depression (CES-D) scale. In 1999, parents reported how often, during the past week, that they experienced 11 depressive symptoms, such as lost appetite, trouble sleeping, and fearfulness. Responses (1 = never, 2 = some of the time, 3 = a moderate amount of time, 4 = most of the time) were averaged to create the final scale (α = .85) (M = 1.41, SD = .49).
Language use at home	In 1998, mothers reported how often they spoke a non-English language at home with their children on a four point scale (1 = never, 2 = sometimes, 3 = often, 4 = very often) (M = 3.51, SD = .88).
Maternal Marital/Partner Characteristics
Marital status	Based on the 1998 household roster, NCES provided a categorical measure for mother’s living situations. From this measure, we created markers for whether mothers were married to or living with child’s father (81%), not married or partnered (13%), or married to or living with someone other than child’s father (5%).
Partner educational attainment	Binary marker designating that the mother was married/partnered to a man who had attended college (10%).
Partner employment status	Binary marker designating that the mother was married/partnered to a man who worked in paid labor force for more than 25 hours per week (64%).
Family Migration Patterns
Mother’s time in U.S.	In 2000, mothers reported how many years that they had been living in the U.S. (M = 11.67, SD = 9.33).
Mother’s education outside U.S.	In 2000, mothers reported how many years of their schooling that they had completed outside the U.S. (M = 7.92, SD = 3.69).
Child born in U.S.	In 1999, mothers reported whether the target child had been born in the U.S. or in another country (12%).