Evaluating School Vouchers: Evidence from a Within-Study Comparison

Randomized Controlled Trials (RCTs) are the “gold-standard” for estimating causal impacts of educational programs. Students subject to lotteries, however, often are not representative of the broader population of students experiencing the educational treatment. With few exceptions, researchers are not able to determine how much selection bias exists when various quasi-experimental approaches are used in place of experimental ones within a school choice context. We are left wondering about the magnitude of the internal-for-external validity tradeoff that education researchers often face. This study assesses the extent to which methods such as propensity score matching or observational models with control variables can replicate the “benchmark” experimental results of the District of Columbia Opportunity Scholarship (DC OSP) school voucher evaluation. The federal private school voucher program is an exemplar subject for study because self-selection is assumed to be a major influence on whether or not a low-income urban student attends a private school. We treat Instrumental Variables Analysis (IV) estimates of the impact of private schooling on student outcomes, some of which are being presented for the first time in this study, as the causal “benchmark” estimate. While our data are fairly limited, and the results relatively imprecise, we find preliminary evidence that covariate choice matters, and that method choice matters, but perhaps only when comparing to a broader sample that includes students who did not apply to the program. Interestingly, we find that the direction of the estimation bias that we detect from some of the quasi-experimental approaches is positive when the sample is limited to program applicants, but negative when it is expanded to include non-applicants. This finding suggests that the applicants to means-tested school voucher programs are negatively selected, but the subgroup of applicants who actually use a voucher if offered tend to be positively selected

Public School Choice and Desegregation in Arkansas

Public school choice is an umbrella term for policies that allow students to enroll in a public school other than their residentially-assigned school. Public school choice, also called openenrollment, is typically divided into two categories: intra-district choice, transfers to schools in the same district, and inter-district choice, transfers to schools in other districts

Understanding a Vicious Cycle: The Relationship Between Student Discipline and Student Academic Outcomes

While numerous studies have demonstrated a correlation between exclusionary discipline and negative student outcomes, this relationship is likely confounded by other factors related to the underlying misbehavior or risk of disciplinary referral. Using 10 years of student-level demographic, achievement, and disciplinary data from all K–12 public schools in Arkansas, we find that exclusionary consequences are related to worse academic outcomes (e.g., test scores and grade retention) than less exclusionary consequences, controlling for type of behavioral infraction. However, despite controlling for a robust set of covariates, sensitivity checks demonstrate that the estimated relationships between consequences and academic outcomes may still be driven by selection bias into consequence type. Implications for policy and practice are discussed

Understanding a Vicious Cycle: Do Out-of-School Suspensions Impact Student Test Scores?

A vast body of research has proven the correlation between exclusionary discipline (out-of-school suspensions and expulsions) and student outcomes such as lower test scores, dropout, grade retention, and involvement in the juvenile justice system, but there is no consensus on the causal impacts of exclusionary discipline. This study uses six years of de-identified demographic, achievement, and disciplinary data from all K-12 public schools in Arkansas to estimate the causal relationship. We conduct dynamic panel data models incorporating student fixed effects using Anderson-Hsiao (1981) estimation. We find, counter-intuitively, a null to positive impact of out-of-school suspensions on test scores. Therefore, while policymakers may have other reasons to limit exclusionary discipline, we should not expect academic gains to follow

You Can’t Always Get What You Want: Using “Broken Lotteries” to Check the Validity of Charter School Evaluations using Matching Designs

We consider situations in which public charter school lotteries are neither universally conducted nor consistently documented. Such lotteries produce “broken” Randomized Control Trials, but provide opportunities to assess the internal validity of quasi-experimental research designs. Here, we present the results of a statewide charter school evaluation using a broad-based student matching evaluation design, and run two additional analyses using the charter application wait-lists as robustness checks. Our additional models, which address concerns of self-selection by using only charter applicants as matched comparison students, yield similar effect estimates and thus provide support for the use of matching designs in charter school evaluations

Congenital Cytomegalovirus Mortality in the United States, 1990–2006

Cytomegalovirus (CMV) is a member of the herpes family of viruses, which is transmitted by sexual and non-sexual contact. Human CMV causes a wide variety of infection and illness in healthy adults, in those with compromised immune systems (such as AIDS), in those with cardiovascular disease, and in pregnant women who can pass the infection to their unborn child (congenital CMV). Treatment options for congenital CMV are limited and no effective vaccine to protect against CMV currently exists. Previous studies have demonstrated that African Americans and Mexican Americans are at an increased risk for congenital CMV infections. In this study, the authors examined death certificate data of US Residents from 1990–2006 in which congenital CMV was listed as one of the diagnoses at death. The analysis demonstrated that there is a significant burden of congenital CMV deaths in infants (<1 year old) with African Americans and Native Americans overrepresented. This study helps quantify congenital CMV deaths among US residents and adds further support to the importance of funding CMV vaccine research

Genomic analysis of diet composition finds novel loci and associations with health and lifestyle

We conducted genome-wide association studies (GWAS) of relative intake from the macronutrients fat, protein, carbohydrates, and sugar in over 235,000 individuals of European ancestries. We identified 21 unique, approximately independent lead SNPs. Fourteen lead SNPs are uniquely associated with one macronutrient at genome-wide significance (P < 5 × 10−8), while five of the 21 lead SNPs reach suggestive significance (P < 1 × 10−5) for at least one other macronutrient. While the phenotypes are genetically correlated, each phenotype carries a partially unique genetic architecture. Relative protein intake exhibits the strongest relationships with poor health, including positive genetic associations with obesity, type 2 diabetes, and heart disease (rg ≈ 0.15–0.5). In contrast, relative carbohydrate and sugar intake have negative genetic correlations with waist circumference, waist-hip ratio, and neighborhood deprivation (|rg| ≈ 0.1–0.3) and positive genetic correlations with physical activity (rg ≈ 0.1 and 0.2). Relative fat intake has no consistent pattern of genetic correlations with poor health but has a negative genetic correlation with educational attainment (rg ≈−0.1). Although our analyses do not allow us to draw causal conclusions, we find no evidence of negative health consequences associated with relative carbohydrate, sugar, or fat intake. However, our results are consistent with the hypothesis that relative protein intake plays a role in the etiology of metabolic dysfunction

Combinatorial hydrogel library enables identification of materials that mitigate the foreign body response in primates

The foreign body response is an immune-mediated reaction that can lead to the failure of implanted medical devices and discomfort for the recipient. There is a critical need for biomaterials that overcome this key challenge in the development of medical devices. Here we use a combinatorial approach for covalent chemical modification to generate a large library of variants of one of the most widely used hydrogel biomaterials, alginate. We evaluated the materials in vivo and identified three triazole-containing analogs that substantially reduce foreign body reactions in both rodents and, for at least 6 months, in non-human primates. The distribution of the triazole modification creates a unique hydrogel surface that inhibits recognition by macrophages and fibrous deposition. In addition to the utility of the compounds reported here, our approach may enable the discovery of other materials that mitigate the foreign body response.Leona M. and Harry B. Helmsley Charitable Trust (3-SRA-2014-285-M-R)United States. National Institutes of Health (EB000244)United States. National Institutes of Health (EB000351)United States. National Institutes of Health (DE013023)United States. National Institutes of Health (CA151884)United States. National Institutes of Health (P41EB015871-27)National Cancer Institute (U.S.) (P30-CA14051

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe