Wavelet Analysis and Denoising: New Tools for Economists

This paper surveys the techniques of wavelets analysis and the associated methods of denoising. The Discrete Wavelet Transform and its undecimated version, the Maximum Overlapping Discrete Wavelet Transform, are described. The methods of wavelets analysis can be used to show how the frequency content of the data varies with time. This allows us to pinpoint in time such events as major structural breaks. The sparse nature of the wavelets representation also facilitates the process of noise reduction by nonlinear wavelet shrinkage , which can be used to reveal the underlying trends in economic data. An application of these techniques to the UK real GDP (1873-2001) is described. The purpose of the analysis is to reveal the true structure of the data - including its local irregularities and abrupt changes - and the results are surprising.Wavelets, Denoising, Structural breaks, Trend estimation

Medicare Hospital Readmissions Reduction Program

Outlines national health reform provisions to reduce readmissions by publishing readmission data, lowering Medicare payments to hospitals with high readmission rates, and pairing such hospitals with patient safety organizations. Considers implications

Schooling and the AFQT: evidence from school entry laws

Is the Armed Forces Qualifying Test (AFQT) a measure of achievement or ability? The answer to this question is critical for drawing inferences from studies in which it is employed. In this paper, we test for a relationship between schooling and AFQT performance in the NLSY 79 by comparing test-takers with birthdays near state cutoff dates for school entry. We instrument for schooling at the test date with academic cohort—the year in which an individual should have entered first grade—in a model that allows age at the test date to have a direct effect on AFQT performance. This identification strategy reveals large impacts of schooling on the AFQT performance of racial minorities, providing support for the hypothesis that the AFQT measures school achievement.Education

Comparative Economic Cycles

The income cycles that have been experienced by six OECD countries over the past 24 years are analysed. The amplitude of the cycles relative to the level of aggregate income varies amongst the countries, as does the degree of the damping that affects the cycles. The study aims to reveal both of these characteristics. It also seeks to determine whether there exists a clear relationship between the degree of damping and the length of the cycles. In order to estimate the parameters of the cycles, the data have been subjected to the processes of detrending, anti-alias filtering and subsampling.Business cycles, Autoregressive models

Sustainable Development Policies in Europe

The objective of this paper is to investigate the actual situation in the shift towards the implementation of Sustainable Development Policies in Europe. The aim is to highlight the key role of the European Union in bringing about sustainable development within Europe and also on the wider global stage. It will show how the European Commission performs its commitment in reaching a sustainable regulation by issuing some documents and declarations. The paper frames the EU action into an international framework of strategies, agreements and policies on SD and, at the same time, provides an overview on experiences of SD strategy implementations at the national level, according to the commission pressing on MS to produce their own SD strategy and implement it. Indicators systems, issues of interest and fields of actions are compared: the analysis of these elements aims to highlight common scenarios of SD strategies that reveal the trends towards a more sustainable growth in the European Union.Sustainable Development, Globalization, Environment Policy, Strategy for Sustainable Development, Good Governance, Participation

Orthogonality Conditions for Non-Dyadic Wavelet Analysis

The conventional dyadic multiresolution analysis constructs a succession of frequency intervals in the form of ( π  / 2  j , π  / 2  j  - 1 ); j  = 1, 2, . . . ,  n of which the bandwidths are halved repeatedly in the descent from high frequencies to low frequencies. Whereas this scheme provides an excellent framework for encoding and transmitting signals with a high degree of data compression, it is less appropriate to the purposes of statistical data analysis.       A non-dyadic mixed-radix wavelet analysis is described that allows the wave bands to be defined more flexibly than in the case of a conventional dyadic analysis. The wavelets that form the basis vectors for the wave bands are derived from the Fourier transforms of a variety of functions that specify the frequency responses of the filters corresponding to the sequences of wavelet coefficients.Wavelets, Non-dyadic analysis, Fourier analysis

Testing for Contagion: a Time-Scale Decomposition

The aim of the paper is to test for ¯nancial contagion by estimating a simultaneous equation model subject to structural breaks. For this purpose, we use the Maximum Overlapping Discrete Wavelet Transform, MODWT, to decompose the covariance matrix of four asset returns on a scale by scale basis. This decomposition will enable us to identify the structural form model and to test for spillover e®ects between country speci¯c shocks during a crisis period. We distinguish between the case of the structural form model with a single dummy and the one with multiple dummies capturing shifts in the co-movement of asset returns occurring during periods of ¯nancial turmoil. The empirical results for four East Asian emerging stock markets show that, once we account for interdependence through an (unobservable) common factor, there is hardly any evidence of contagion during the 1997-1998 financial turbulence.wavelets; simultaneous equations model; financial contagion

First in the Class? Age and the Education Production Function

We estimate the effects of having more mature peers using data from an experiment where children of the same age were randomly assigned to different kindergarten classrooms. Exploiting this experimental variation in conjunction with variation in expected kindergarten entry age to account for negative selection of older school entrants, we find that exposure to more mature kindergarten classmates raises test scores up to eight years after kindergarten, and may reduce the incidence of grade retention and increase the probability of taking a college-entry exam. These findings are consistent with broader peer effects literature documenting positive spillovers from having higher-scoring peers and suggest that – contrary to much academic and popular discussion of school entry age – being old relative to one’s peers is not beneficial.

Reduced relationship to cortical white matter volume revealed by Tractography-based segmentation of the corpus callosum in young children with developmental delay

pre-printObjective: The corpus callosum is the primary anatomical substrate for inter-hemispheric communication, which is important for a range of adaptive and cognitive behaviors in early development. Previous studies that have measured the corpus callosum in developmental populations have been limited by the use of rather arbitrary methods of subdividing the corpus callosum. The purpose of this study was to measure the corpus callosum in a clinical group of developmentally delayed children using a subdivision that more accurately reflected the anatomical properties of the corpus callosum. Method: The authors applied tractography to subdivide the corpus callosum into regions corresponding to the cortical regions to and from which its fibers travel in a clinical group of very young children with evelopmental delay, a precursor to general mental retardation, in comparison with typically developing children. Results: The data demonstrate that the midsagittal area of the entire corpus callosum is reduced in children presenting with developmental delay, reflected in the smaller area of each of the fiberbased callosal subdivisions. In addition, while the area of each subdivision was strongly and significantly correlated with the corresponding cortical white matter volume in comparison subjects, this correlation was prominently absent in the developmentally delayed group. Conclusions: A fiber-based subdivision successfully separates lobar regions of the corpus callosum, and the areas of these regions distinguish a developmentally delayed clinical group from the comparison group. This distinction was evident both in the area measurements themselves and in their correlation to the white matter volumes of the corresponding cortical lobes

Education and Intergenerational Mobility: Evidence from a Natural Experiment in Purerto Rico

The existence of intergenerational spillovers to public investments in schooling is often assumed in policy discussions regarding economic development. However, few studies to date have forwarded convincing evidence that externalities exist for developing countries. In this paper, we address this issue using the arguably exogenous schooling consequences of a major hurricane strike on Puerto Rico in the 1950s. Using data from the US. Census of Population for Puerto Rico, we first find that individuals on to margin of school entry at the time of the storm and residing in the most exposed regions of the island had significantly lower levels of education as adults than their counterparts in less exposed regions. Using the interaction of wind speed and age at the time of the storm as an instrument, we then find that maternal education is related to the probability that a child speaks English. Our estimates imply an additional year of education raise the probability that a child speaks English by between 4.3 and 4.5 percentage points, c approximately 24 to 28 percent. We find no conclusive evidence that parental education increases the probability that a child is enrolled, literate, or in an age-appropriate grad, On balance, these findings suggest that education is responsible at least in part for the persistence of human capital across generations.education, intergenerational mobility, natural experiment, hurricane