Childcare Policy and Cognitive Outcomes of Children: Results from a Large Scale Quasi-Experiment on Universal Childcare in Canada

Effects of a low-fee universal childcare policy, initiated in Québec, the second most populous province in Canada, on the cognitive development of preschool children are estimated with a sample of 4- and 5-year-olds (N=8,875; N=17,154). In 1997, licensed and regulated providers of childcare services began offering daycare spaces at the reduced fee of $5 per day per child for children aged 4. By 2000, the low-fee policy applied to all children aged 0 to 59 months (not in kindergarten). The study uses 6 cycles of biennial data drawn from Statistics Canada's National Longitudinal Survey of Children and Youth (1994-2004) and quasi-experimental estimation methods to provide evidence that the policy had substantial negative effects on preschool children's Peabody Picture Vocabulary Test scores. The negative effects are found to be stronger for children with mothers who have lower levels of education.Preschool children, school readiness, childcare, kindergarten, treatment effects, natural experiment

The Effects of School Quality and Family Functioning on Youth Math Scores: a Canadian Longitudinal Analysis

This paper tries to disentangle the relative importance of family and school inputs on a child's cognitive achievement as measured by her percentile score on a mathematics test. We replicate a study by Todd and Wolpin (2007) in the United States with Canadian data. In contrast to their work that uses state-level indicators of school quality, we estimate our model with data from Statistics Canada's National Longitudinal Survey of Children and Youth (NLSCY) which provides micro-level information on the family and school history of the child. The sample used for the analysis is based on the 7- to 15-year-old longitudinal children who have completed at least two consecutive math tests. As in Todd and Wolpin, we conclude that cognitive outcomes are determined by current and past family inputs. Contrary to them, who find no impact of school inputs, we find that the quality of schools has a positive impact on achievement in mathematics.Math scores, human capital, child development, school and family inputs, panel data

Impact of Early Childhood Care and Education on Children's Preschool Cognitive Development: Canadian Results from a Large Quasi-experiment

On September 1st 1997, a new early childhood care and education policy was initiated by the provincial government of Québec, the second most populous province in Canada. Providers of childcare services licensed by the Department of the Family began offering daycare spaces at the reduced parental contribution of $5 per day per child for children aged 4. In successive years, the government reduced the age requirement and engaged in a plan to create new childcare facilities and pay for the cost of additional$5 per day childcare spaces. By September 2000, the low-fee policy applied to all children aged 0 to 59 months and the number of partly subsidized spaces increased from 77,000 in 1998 to 170,000 spaces, totally subsidized, by midyear 2003. In addition, on September 1st 1997, all public schools offered full-day rather than part-day kindergarten for 5-year-old children. No such important policy changes for preschool (including kindergarten) children were enacted in the other Canadian provinces over the years 1994 to 2003. Using biennial data drawn from Statistics Canada’s National Longitudinal Survey of Children and Youth (NLSCY), conducted since 1994-1995, this study attempts to estimate the effect of the policy on Québec’s preschool children cognitive test scores. A non-experimental evaluation framework based on multiple pre- and post-treatment periods is used to estimate the effect of the early childhood care and education regime on school readiness. The econometric results support the hypothesis that the policy had no effects on the cognitive development of 4-year-olds (the PPVT-R raw scores and the PPVT-R standardized scores). However, we provide evidence that the policy had a substantial negative impact on the scores of 5-year-olds.preschool children, school readiness, childcare, kindergarten, treatment effects, natural experiment

Density functional perturbation theory within non-collinear magnetism

We extend the density functional perturbation theory formalism to the case of non-collinear magnetism. The main problem comes with the exchange-correlation (XC) potential derivatives, which are the only ones that are affected by the non-collinearity of the system. Most of the present XC functionals are constructed at the collinear level, such that the off-diagonal (containing magnetization densities along $x$ and $y$ directions) derivatives cannot be calculated simply in the non-collinear framework. To solve this problem, we consider here possibilities to transform the non-collinear XC derivatives to a local collinear basis, where the $z$ axis is aligned with the local magnetization at each point. The two methods we explore are i) expanding the spin rotation matrix as a Taylor series, ii) evaluating explicitly the XC for the local density approximation through an analytical expression of the expansion terms. We compare the two methods and describe their practical implementation. We show their application for atomic displacement and electric field perturbations at the second order, within the norm-conserving pseudopotential methods

L'impact sur le développement cognitif des enfants âgés de 4 et 5 ans de la politique de garde à 5$ du Québec

Cette étude cherche à évaluer l'impact sur le développement cognitif de jeunes enfants âgés de 4 et 5 ans de la politique de garde à 5 mise en place au Québec en septembre 1997, en utilisant les données des 5 cycles de l'Enquête Longitudinale Nationale sur les Enfants et les Jeunes (ELNEJ). Plus précisément, le développement cognitif est mesuré par le score standardisé obtenu à un test de vocabulaire (ÉVIP-R). La méthode de standardisation du score cognitif n'étant pas identique pour tous les cycles, l'ampleur des effets trouvés pour l'ÉVIP-R est donc sujette à caution. La modélisation économétrique est basée sur les méthodes des différences-en-différences (DD) et des différences-en-différences-en-différences (DDD), et tient compte d'un nombre important de caractéristiques familiales. Les enfants québécois constituent donc le groupe de traitement tandis que le reste des enfants canadiens représente le groupe de contrôle. Les résultats des estimations suggèrent que cette politique n'a eu d'effet significatif sur le développement cognitif que pour les enfants québécois âgés de 5 ans. Cet effet est négatif et assez faible. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Développement cognitif, Garderie à 5, Différences-en-différences

Impact of Early Childhood Care and Education on Children's Preschool Cognitive Development: Canadian Results from a Large Quasi-experiment

On September 1st 1997, a new early childhood care and education policy was initiated by the provincial government of Québec, the second most populous province in Canada. Providers of childcare services licensed by the Department of the Family began offering daycare spaces at the reduced parental contribution of $5 per day per child for children aged 4. In successive years, the government reduced the age requirement and engaged in a plan to create new childcare facilities and pay for the cost of additional$5 per day childcare spaces. By September 2000, the low-fee policy applied to all children aged 0 to 59 months and the number of partly subsidized spaces increased from 77,000 in 1998 to 170,000 spaces, totally subsidized, by midyear 2003. In addition, on September 1st 1997, all public schools offered full-day rather than part-day kindergarten for 5-year-old children. No such important policy changes for preschool (including kindergarten) children were enacted in the other Canadian provinces over the years 1994 to 2003. Using biennial data drawn from Statistics Canada’s National Longitudinal Survey of Children and Youth (NLSCY), conducted since 1994-1995, this study attempts to estimate the effect of the policy on Québec’s preschool children cognitive test scores. A non-experimental evaluation framework based on multiple pre- and post-treatment periods is used to estimate the effect of the early childhood care and education regime on school readiness. The econometric results support the hypothesis that the policy had no effects on the cognitive development of 4-year-olds (the PPVT-R raw scores and the PPVT-R standardized scores). However, we provide evidence that the policy had a substantial negative impact on the scores of 5-year-olds

Vibrational and dielectric properties of monolayer transition metal dichalcogenides

First-principles studies of two-dimensional transition metal dichalcogenides have contributed considerably to the understanding of their dielectric, optical, elastic, and vibrational properties. The majority of works to date focus on a single material or physical property. Here we use a single first-principles methodology on the whole family of systems, to investigate in depth the relationships between different physical properties, the underlying symmetry and the composition of these materials, and observe trends. We compare to bulk counterparts to show strong interlayer effects in triclinic compounds. Previously unobserved relationships between these monolayer compounds become apparent. These trends can then be exploited by the materials science, nanoscience, and chemistry communities to better design devices and heterostructures for specific functionalities.Comment: 4 figures, 11 page

Vibrational and dielectric properties of the bulk transition metal dichalcogenides

Interest in the bulk transition metal dichalcogenides for their electronic, photovoltaic, and optical properties has grown and led to their use in many technological applications. We present a systematic investigation of their interlinked vibrational and dielectric properties, using density functional theory and density functional perturbation theory, studying the effects of the spin-orbit interaction and of the long-range e$^-$- e$^-$ correlation as part of our investigation. This study confirms that the spin-orbit interaction plays a small role in these physical properties, while the direct contribution of dispersion corrections is of crucial importance in the description of the interatomic force constants. Here, our analysis of the structural and vibrational properties, including the Raman spectra, compare well to experimental measurement. Three materials with different point groups are showcased and data trends on the full set of fifteen existing hexagonal, trigonal, and triclinic materials are demonstrated. This overall picture will enable the modeling of devices composed of these materials for novel applications.Comment: 11 pages, 6 figure