Consumption smoothing and the measured regressivity of consumption taxes

In this article, we address two questions. First, how will a move to pure consumption taxation matter for aggregate outcomes? Second, how regressive are consumption taxes? We find as follows. First, a move to a consumption tax will increase savings taken into retirement but will not alter either labor supply or consumption variability substantially. Second, we show that regressivity is a measure that is quantitatively sensitive to the frequency of income being used. In particular, we show that when measures of tax incidence are based on annual income, successful consumption smoothing leads to the appearance of high regressivity. Our preferred measure, which is based on lifetime earnings, shows that consumption taxes are proportional taxes.Taxation ; Consumption (Economics)

Imputation Approaches for Animal Movement Modeling

The analysis of telemetry data is common in animal ecological studies. While the collection of telemetry data for individual animals has improved dramatically, the methods to properly account for inherent uncertainties (e.g., measurement error, dependence, barriers to movement) have lagged behind. Still, many new statistical approaches have been developed to infer unknown quantities affecting animal movement or predict movement based on telemetry data. Hierarchical statistical models are useful to account for some of the aforementioned uncertainties, as well as provide population-level inference, but they often come with an increased computational burden. For certain types of statistical models, it is straightforward to provide inference if the latent true animal trajectory is known, but challenging otherwise. In these cases, approaches related to multiple imputation have been employed to account for the uncertainty associated with our knowledge of the latent trajectory. Despite the increasing use of imputation approaches for modeling animal movement, the general sensitivity and accuracy of these methods have not been explored in detail. We provide an introduction to animal movement modeling and describe how imputation approaches may be helpful for certain types of models. We also assess the performance of imputation approaches in a simulation study. Our simulation study suggests that inference for model parameters directly related to the location of an individual may be more accurate than inference for parameters associated with higher-order processes such as velocity or acceleration. Finally, we apply these methods to analyze a telemetry data set involving northern fur seals (Callorhinus ursinus) in the Bering Sea

Earned income tax credit recipients: income, marginal tax rates, wealth, and credit constraints

The Earned Income Tax Credit (EITC) has evolved into the largest anti-poverty program in the United States by providing tax credits for low and moderate income working families. In this paper, we describe the characteristics of EITC recipients at various ages using Current Population Survey data. In addition, we discuss the relevance of the EITC in affecting marginal income tax rates in the United States and discuss the effects of the EITC on household labor supply decisions. Lastly, using data from the Survey of Consumer Finances, we estimate wealth distributions for EITC recipients and analyze the extent to which EITC recipients are credit constrained.Credit ; Taxation

Single Mothers and the Earned Income Tax Credit: Insurance Without Disincentives?

The Earned Income Tax Credit (EITC) is the single most important transfer program in place in the United States. An aspect of the EITC that has received little attention thus far is its role as a public insurance program. Yet, the structure of the EITC necessarily protects its primary class of recipients, unskilled single mothers, against major risks they face to both wages and changes in family structure. Our study provides the first quantitative statement about the insurance provided by the EITC. We study a dynamic model of consumption, savings, and labor supply in which households face wage and demographic risk, but have only limited self-insurance capacity. We use the model to compare outcomes under the EITC to the counterfactual in which it is completely eliminated. We find that the EITC provides substantial insurance to unskilled single mothers: The program reduces consumption volatility, as measured by the coefficient of the variation, by 12 percentage points or more, even as it allows these households to save less. Importantly, this insurance provision may not be compromising incentives to work: The model suggests that the EITC increases the labor supply of unskilled single mothers substantially at the extensive margin

An intracellular traffic jam: Fc receptor-mediated transport of immunoglobulin G

Recent advances in imaging techniques along with more powerful in vitro and in vivo models of receptor-mediated ligand transport are facilitating advances in our understanding of how cells efficiently direct receptors and their cargo to target destinations within the cytoplasm and at the plasma membrane. Specifically, light and 3D electron microscopy studies examining the trafficking behavior of the neonatal Fc receptor (FcRn), a transport receptor for immunoglobulin G (IgG), have given us new insights into the dynamic interplay between the structural components of the cytosolic trafficking machinery, its protein regulators, and the receptors it directs to various locations within the cell. These studies build upon previous biochemical characterizations of FcRn transport and are allowing us to begin formulation of a more complete model for the intracellular trafficking of receptor–ligand complexes

Family and Peer Influences on Substance Attitudes and Use among Juvenile Justice-Involved Youth

Juvenile justice-involved youth experience high rates of substance use, which is concerning given associated negative consequences, including health and functional deficits. Family and peer factors are associated with a high risk of substance use among justice-involved youth. It is hypothesized that this risk process operates through pro-drug attitudes. However, limited research has been conducted on the mechanisms through which family and peer factors increase risk for substance use among juvenile justice involved youth. The current study examined both the direct and indirect effects of family and peer substance use on youth's substance use (alcohol and illicit drug use). We also examined whether this relationship differs by race. 226 detained youth (81.9% male; 74.3% Black) were recruited from an urban county in the Midwest and completed a clinical interview and substance use assessment battery. A direct effect of family/peer risk on illicit drug use was found for all youth, though the effect was stronger among White youth. Results also supported the indirect effect pathway from family/peer risk to both illicit drug use and alcohol use through pro-drug attitudes. This pathway did not vary by race. These findings suggest that interventions should focus on targeting both family/peer risk and pro-drug attitudes to reduce substance use. Given the racial difference in the direct effect of family/peer risk on illicit drug use, there may be other factors that influence risk more strongly for White youth, which warrants further investigation

Development and application of a spatially-explicit nitrogen mass-balance model for the Wood River Valley Watershed, Idaho

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.Includes bibliographical references (p. 155-162).by Julianna B. Connolly and Devin L. Shaffer.M.Eng