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Accurate understanding of environmental moderation of genetic influences is vital to advancing the science of cognitive development as well as for designing interventions. One widely- reported idea is increasing genetic influence on cognition for children raised in higher socioeconomic status families, including recent proposals that the pattern is a particularly US phenomenon. We use matched birth and school records from Florida siblings and twins born in 1994-2002 to provide the largest, most population-diverse consideration of this hypothesis to date. We find no evidence of SES moderation of genetic influence on test scores, suggesting that articulating gene-environment interactions for cognition is more complex and elusive than previously supposed.
Citation: David Figlio, Jeremy Freese, Krzysztof Karbownik, Jeffrey Roth (2018). Socioeconomic Status and Genetic Influences on Cognitive Development. CALDER Working Paper No. 193
It is notoriously difficult to identify peer effects within the family because of the common shocks and reflection problems. We make use of a novel identification strategy and unique data in order to gain some purchase on this problem. We employ data from the universe of children born in Florida between 1994 and 2002 and in Denmark between 1990 and 2001, which we match to school and medical records. To address the identification problem, we examine the effects of having a sibling with a disability. Utilizing three-plus-child families, we employ a differences-in- differences research design which makes use of the fact that birth order influences the amount of time that a child spends in early childhood with their siblings, disabled or not. We observe consistent evidence in both locations that the second child in a family is differentially affected when the third child is disabled.
Citation: Sandra E. Black, Sanni Breining, David Figlio, Jonathan Guryan, Krzysztof Karbownik, Helena Skyt Nielsen, Jeffrey Roth, Marianne Simonsen (2018). Sibling Spillovers. CALDER Working Paper No. 192
We present evidence of a positive relationship between school starting age and children’s cognitive development from age 6 to 18 using a fuzzy regression discontinuity design and large-scale population-level birth and school data from the state of Florida. We estimate effects of being old for grade (being born in September versus August) that are remarkably stable – always around 0.2 SD difference in test scores – across a wide range of heterogeneous groups, based on maternal education, poverty at birth, race/ethnicity, birth weight, gestational age, and school quality. While the September-August difference in kindergarten readiness is dramatically different by subgroup, by the time students take their first exams, the heterogeneity in estimated effects on test scores effectively disappears. We do, however, find significant heterogeneity in other outcome measures such as disability status and middle and high school course selections. We also document substantial variation in compensatory behaviors targeted towards young for grade children. While the more affluent families tend to redshirt their children, young for grade children from less affluent families are more likely to be retained in grades prior to testing. School district practices regarding retention and redshirting are correlated with improved out- comes for the groups less likely to use those remediation approaches (i.e., retention in the case of more-affluent families and redshirting in the case of less-affluent families.) Finally, we find that very few school policies or practices mitigate the test score advantage of September born children.
Millions of tons of hazardous wastes have been produced in the United States in the last 60 years which have been dispersed into the air, into water, and on and under the ground. Using new population-level data that follows cohorts of children born in the state of Florida between 1994 and 2002, this paper examines the short and long-term effects of prenatal exposure to environmental toxicants on children living within two miles of a Superfund site, toxic waste sites identified by the Environmental Protection Agency as being particularly severe. We compare siblings living within two miles from a Superfund site at birth where at least one sibling was conceived before or during cleanup of the site, and the other(s) was conceived after the site cleanup was completed using a family fixed effects model. Children conceived to mothers living within 2 miles of a Superfund site before it was cleaned are 7.4 percentage points more likely to repeat a grade, have 0.06 of a standard deviation lower test scores, and are 6.6 percentage points more likely to be suspended from school than their siblings who were conceived after the site was cleaned. Children conceived to mothers living within one mile of a Superfund site before it was cleaned are 10 percentage points more likely to be diagnosed with a cognitive disability than their later born siblings as well. These results tend to be larger and are more statistically significant than the estimated effects of proximity to a Superfund site on birth outcomes. This study suggests that the cleanup of severe toxic waste sites has significant positive effects on a variety of long-term cognitive and developmental outcomes for children.
Citation: Claudia Persico, David Figlio, Jeffrey Roth (2016). Inequality Before Birth: The Developmental Consequences of Environmental Toxicants. CALDER Working Paper No. 160
This study examines the community-wide effects of two statewide early childhood policy initiatives in North Carolina. One initiative provides funding to improve the quality of child care services at the county level for all children between the ages of 0 to 5, and the other provides funding for preschool slots for disadvantaged four-year-olds. Differences across counties in the timing of the rollout and in the magnitude of the state financial investments per child provide the variation in programs needed to estimate their effects on schooling outcomes in third grade. We find robust positive effects of each program on third-grade test scores in both reading and math. These effects can best be explained by a combination of direct benefits for participants and spillover benefits for others. Our preferred models suggest that the combined average effects on test scores of investments in both programs at 2009 funding levels are equivalent to two to four months of instruction in grade 3.
Citation: Helen Ladd, Clara G. Muschkin, Kenneth A. Dodge (2015). From Birth to School: Early Childhood Initiatives and Third-Grade Outcomes in North Carolina. CALDER Working Paper No. 134
This study examines the community-wide effects of investments in two early childhood initiatives in North Carolina (Smart Start and More at Four) on the likelihood of a student being placed into special education. We take advantage of variation across North Carolina counties and years in the timing of the introduction and funding levels of the two programs to identify their effects on third-grade outcomes. We find that both programs significantly reduce the likelihood of special education placement in the third grade, resulting in considerable cost savings to the state. The effects of the two programs differ across categories of disability, but do not vary significantly across subgroups of children identified by race, ethnicity, and maternal education levels.
Citation: Clara Muschkin, Helen Ladd, Kenneth Dodge (2015). Impact of North Carolina’s Early Childhood Initiatives on Special Education Placements in Third Grade. CALDER Working Paper No. 121
We make use of a new data resource, merged birth and school records for all children born in Florida from 1992 to 2002, to study the effects of birth weight on cognitive development from kindergarten through schooling. Using twin fixed effects models, we find that the effects of birth weight on cognitive development are essentially constant through the school career; that these effects are very similar across a wide range of family backgrounds; and that they are invariant to measures of school quality. We conclude that the effects of poor neonatal health on adult outcomes are therefore set very early.
Citation: David Figlio, Jonathan Guryan, Kryzsztof Karbownik, Jeffrey Roth (2013). The Effects of Poor Neonatal Health on Children’s Cognitive Development. CALDER Working Paper No. 95
There has been a resurgence in research that investigates the efficacy of early investments as a means of reducing gaps in academic performance. However, the strongest evidence for these effects comes from experimental evaluations of small, highly enriched programs. We add to this literature by assessing the extent to which a large-scale public program, Texas's targeted pre-Kindergarten (pre-K), affects scores on math and reading achievement tests, the likelihood of being retained in grade, and the probability that a student receives special education services. We find that having participated in Texas's targeted pre-K program is associated with increased scores on the math and reading sections of the Texas Assessment of Academic Skills (TAAS), reductions in the likelihood of being retained in grade, and reductions in the probability of receiving special education services. We also find that participating pre-K increases mathematics scores for students who take the Spanish version of the TAAS tests. These results show that even modest, public pre-K program implemented at scale can have important effects on students’ educational achievement.
Citation: Rodney J. Andrews, Paul Jargowsky, Kristin Kuhne (2012). The Effects of Texas’s Targeted Pre-Kindergarten Program on Academic Performance. CALDER Working Paper No. 84