Download or read book Inference on Structural Changes in High Dimensional Linear Regression Models written by Hongjin Zhang and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is dedicated to studying the problem of constructing asymptotically valid confidence intervals for change points in high-dimensional linear models, where the number of parameters may vastly exceed the sampling period.In Chapter 2, we develop an algorithmic estimator for a single change point and establish the optimal rate of estimation, Op(Îl 8́22 ), where Îl represents the jump size under a high dimensional scaling. The optimal result ensures the existence of limiting distributions. Asymptotic distributions are derived under both vanishing and non-vanishing regimes of jump size. In the former case, it corresponds to the argmax of a two-sided Brownian motion, while in the latter case to the argmax of a two-sided random walk, both with negative drifts. We also provide the relationship between the two distributions, which allows construction of regime (vanishing vs non-vanishing) adaptive confidence intervals.In Chapter 3, we extend our analysis to the statistical inference for multiple change points in high-dimensional linear regression models. We develop locally refitted estimators and evaluate their convergence rates both component-wise and simultaneously. Following similar manner as in Chapter 2, we achieve an optimal rate of estimation under the component-wise scenario, which guarantees the existence of limiting distributions. While we also establish the simultaneous rate which is the sharpest available by a logarithmic factor. Component-wise and joint limiting distributions are derived under vanishing and non-vanishing regimes of jump sizes, demonstrating the relationship between distributions in the two regimes.Lastly in Chapter 4, we introduce a novel implementation method for finding preliminary change points estimates via integer linear programming, which has not yet been explored in the current literature.Overall, this dissertation provides a comprehensive framework for inference on single and multiple change points in high-dimensional linear models, offering novel and efficient algorithms with strong theoretical guarantees. All theoretical results are supported by Monte Carlo simulations.
Download or read book Inference Regarding Multiple Structural Changes in Linear Models Estimated via Two Stage Least Squares written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Bai and Perron(1998) develop methods that are designed to test for structural stability with an unknown number of break points in the sample. Their analysis is in the context of linear regression models estimated via Ordinary Least Squares(OLS). We extend Bai and Perron's framework for multiple break testing to linear models via Two Stage Least Squares(2SLS). Within our framework, the break points are estimated simultaneously with the regression parameters via minimization of the residual sum of squares on the second step of the 2SLS estimation. We establish the consistency of the resulting estimated break point fractions and obtain the standard convergence rate of break fraction estimators. Based on that convergence rate we derive the limiting distribution of the break point estimators. We prove that the break point estimator have the same limiting distribution of the arg max of two sided Brownian motion process, which is the same distribution considered by Bai and Perron(1998). We also show that various F-statistics for structural instability based on the 2SLS estimator have the same limiting distribution as the analogous statistics for OLS considered by Bai and Perron(1998). This allows us to extend Bai and Perron's(1998) sequential procedure for selecting the number of break points to the 2SLS setting. Simulation experiment and application to financial market has been implemented.
Download or read book Sequential Analysis written by Alexander Tartakovsky and published by CRC Press. This book was released on 2014-08-27 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sequential Analysis: Hypothesis Testing and Changepoint Detection systematically develops the theory of sequential hypothesis testing and quickest changepoint detection. It also describes important applications in which theoretical results can be used efficiently. The book reviews recent accomplishments in hypothesis testing and changepoint detecti
Download or read book High dimensional Regression Models with Structured Coefficients written by Yuan Li and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Regression models are very common for statistical inference, especially linear regression models with Gaussian noise. But in many modern scientific applications with large-scale datasets, the number of samples is small relative to the number of model parameters, which is the so-called high- dimensional setting. Directly applying classical linear regression models to high-dimensional data is ill-posed. Thus it is necessary to impose additional assumptions for regression coefficients to make high-dimensional statistical analysis possible. Regularization methods with sparsity assumptions have received substantial attention over the past two decades. But there are still some open questions regarding high-dimensional statistical analysis. Firstly, most literature provides statistical analysis for high-dimensional linear models with Gaussian noise, it is unclear whether similar results still hold if we are no longer in the Gaussian setting. To answer this question under Poisson setting, we study the minimax rates and provide an implementable convex algorithm for high-dimensional Poisson inverse problems under weak sparsity assumption and physical constraints. Secondly, much of the theory and methodology for high-dimensional linear regression models are based on the assumption that independent variables are independent of each other or have weak correlations. But it is possible that this assumption is not satisfied that some features are highly correlated with each other. It is natural to ask whether it is still possible to make high-dimensional statistical inference with high-correlated designs. Thus we provide a graph-based regularization method for high-dimensional regression models with high-correlated designs along with theoretical guarantees.
Download or read book Inference for High dimensional Sparse Econometric Models written by Alexandre Belloni and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This article is about estimation and inference methods for high dimensional sparse (HDS) regression models in econometrics. High dimensional sparse models arise in situations where many regressors (or series terms) are available and the regression function is well-approximated by a parsimonious, yet unknown set of regressors. The latter condition makes it possible to estimate the entire regression function effectively by searching for approximately the right set of regressors. We discuss methods for identifying this set of regressors and estimating their coefficients based on l1 -penalization and describe key theoretical results. In order to capture realistic practical situations, we expressly allow for imperfect selection of regressors and study the impact of this imperfect selection on estimation and inference results. We focus the main part of the article on the use of HDS models and methods in the instrumental variables model and the partially linear model. We present a set of novel inference results for these models and illustrate their use with applications to returns to schooling and growth regression. -- inference under imperfect model selection ; structural effects ; high-dimensional econometrics ; instrumental regression ; partially linear regression ; returns-to-schooling ; growth regression
Download or read book Sparse Graphical Modeling for High Dimensional Data written by Faming Liang and published by CRC Press. This book was released on 2023-08-02 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: A general framework for learning sparse graphical models with conditional independence tests Complete treatments for different types of data, Gaussian, Poisson, multinomial, and mixed data Unified treatments for data integration, network comparison, and covariate adjustment Unified treatments for missing data and heterogeneous data Efficient methods for joint estimation of multiple graphical models Effective methods of high-dimensional variable selection Effective methods of high-dimensional inference
Download or read book Partially Linear Models written by Wolfgang Härdle and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last ten years, there has been increasing interest and activity in the general area of partially linear regression smoothing in statistics. Many methods and techniques have been proposed and studied. This monograph hopes to bring an up-to-date presentation of the state of the art of partially linear regression techniques. The emphasis is on methodologies rather than on the theory, with a particular focus on applications of partially linear regression techniques to various statistical problems. These problems include least squares regression, asymptotically efficient estimation, bootstrap resampling, censored data analysis, linear measurement error models, nonlinear measurement models, nonlinear and nonparametric time series models.
Download or read book Statistical Inference for High Dimensional Linear Models written by Zijian Guo and published by . This book was released on 2017 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-dimensional linear models play an important role in the analysis of modern data sets. Although the estimation problem has been well understood, there is still a paucity of methods and theories on the inference problem for high-dimensional linear models. This thesis focuses on statistical inference for high-dimensional linear models and consists of the following three parts. 1. The first part of the thesis considers confidence intervals for linear functionals in high-dimensional linear regression. We first establish the convergence rates of the minimax expected length for confidence intervals. Furthermore, we investigate the problem of adaptation to sparsity for the construction of confidence intervals and identify the regimes in which it is possible to construct adaptive confidence intervals. 2. In the second part of the thesis, we consider point and interval estimation of the lq loss of a given estimator in high-dimensional linear regression. For the class of rate-optimal estimators, we establish the minimax rates for estimating their lq losses, the minimax expected length of confidence intervals for their lq losses and the possibility of adaptivity of confidence intervals for their lq losses. 3. In the third part of the thesis, we consider the problem in the framework of high-dimensional instrumental variable regression and construct confidence intervals for the treatment effect in the presence of possibly invalid instrumental variables. We develop a novel selection procedure, Two-Stage Hard Thresholding (TSHT) to select valid instrumental variables and construct honest confidence intervals for the treatment effect using the selected instrumental variables.
Download or read book Inference in High Dimensional Linear Regression Models written by Tom Boot and published by . This book was released on 2017 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: We introduce an asymptotically unbiased estimator for the full high-dimensional parameter vector in linear regression models where the number of variables exceeds the number of available observations. The estimator is accompanied by a closed-form expression for the covariance matrix of the estimates that is free of tuning parameters. This enables the construction of confidence intervals that are valid uniformly over the parameter vector. Estimates are obtained by using a scaled Moore-Penrose pseudoinverse as an approximate inverse of the singular empirical covariance matrix of the regressors. The approximation induces a bias, which is then corrected for using the lasso. Regularization of the pseudoinverse is shown to yield narrower confidence intervals under a suitable choice of the regularization parameter. The methods are illustrated in Monte Carlo experiments and in an empirical example where gross domestic product is explained by a large number of macroeconomic and financial indicators.
Download or read book Large dimensional Panel Data Econometrics Testing Estimation And Structural Changes written by Feng Qu and published by World Scientific. This book was released on 2020-08-24 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to fill the gap between panel data econometrics textbooks, and the latest development on 'big data', especially large-dimensional panel data econometrics. It introduces important research questions in large panels, including testing for cross-sectional dependence, estimation of factor-augmented panel data models, structural breaks in panels and group patterns in panels. To tackle these high dimensional issues, some techniques used in Machine Learning approaches are also illustrated. Moreover, the Monte Carlo experiments, and empirical examples are also utilised to show how to implement these new inference methods. Large-Dimensional Panel Data Econometrics: Testing, Estimation and Structural Changes also introduces new research questions and results in recent literature in this field.
Download or read book Inference Regarding Multiple Structural Changes in Linear Models Estimated Via Two Stage Least Squares written by Sanggohn Han and published by . This book was released on 2005 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: two stage least squares, break fraction estimators, multiple structural changes.
Download or read book High dimensional Econometrics And Identification written by Kao Chihwa and published by World Scientific. This book was released on 2019-04-10 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: In many applications of econometrics and economics, a large proportion of the questions of interest are identification. An economist may be interested in uncovering the true signal when the data could be very noisy, such as time-series spurious regression and weak instruments problems, to name a few. In this book, High-Dimensional Econometrics and Identification, we illustrate the true signal and, hence, identification can be recovered even with noisy data in high-dimensional data, e.g., large panels. High-dimensional data in econometrics is the rule rather than the exception. One of the tools to analyze large, high-dimensional data is the panel data model.High-Dimensional Econometrics and Identification grew out of research work on the identification and high-dimensional econometrics that we have collaborated on over the years, and it aims to provide an up-todate presentation of the issues of identification and high-dimensional econometrics, as well as insights into the use of these results in empirical studies. This book is designed for high-level graduate courses in econometrics and statistics, as well as used as a reference for researchers.
Download or read book Analysis of Panel Data written by Cheng Hsiao and published by Cambridge University Press. This book was released on 2022-07-07 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive introduction of fundamental panel data methodologies.
Download or read book Cross validation and Regression Analysis in High dimensional Sparse Linear Models written by Feng Zhang and published by Stanford University. This book was released on 2011 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern scientific research often involves experiments with at most hundreds of subjects but with tens of thousands of variables for every subject. The challenge of high dimensionality has reshaped statistical thinking and modeling. Variable selection plays a pivotal role in the high-dimensional data analysis, and the combination of sparsity and accuracy is crucial for statistical theory and practical applications. Regularization methods are attractive for tackling these sparsity and accuracy issues. The first part of this thesis studies two regularization methods. First, we consider the orthogonal greedy algorithm (OGA) used in conjunction with a high-dimensional information criterion introduced by Ing& Lai (2011). Although it has been shown to have excellent performance for weakly sparse regression models, one does not know a priori in practice that the actual model is weakly sparse, and we address this problem by developing a new cross-validation approach. OGA can be viewed as L0 regularization for weakly sparse regression models. When such sparsity fails, as revealed by the cross-validation analysis, we propose to use a new way to combine L1 and L2 penalties, which we show to have important advantages over previous regularization methods. The second part of the thesis develops a Monte Carlo Cross-Validation (MCCV) method to estimate the distribution of out-of-sample prediction errors when a training sample is used to build a regression model for prediction. Asymptotic theory and simulation studies show that the proposed MCCV method mimics the actual (but unknown) prediction error distribution even when the number of regressors exceeds the sample size. Therefore MCCV provides a useful tool for comparing the predictive performance of different regularization methods for real (rather than simulated) data sets.
Download or read book Estimating and Testing Linear Models with Multiple Structural Changes written by Jushan Bai and published by . This book was released on 1995 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamic Causal Inference with Imperfect Identifying Information written by Lam Hoang Nguyen and published by . This book was released on 2020 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation contains three essays exploring how macroeconomists can identify and estimate dynamic causal effects in models where researchers have doubts about identifying assumptions. Chapter 1 proposes a new Markov Chain Monte Carlo algorithm to estimate a sign-restricted structural vector autoregression on time series that are subject to regime shifts. My approach can incorporate useful prior information about both model parameters and hidden states while transparently imposing sign restrictions. I illustrate my method by revisiting the literature on asymmetric effects of conventional monetary policy during recessions and expansions. My evidence suggests that previous empirical research found asymmetric effects by questionable identification schemes and neglecting changes in the variances of structural shocks. I find little difference in the structural parameters, and thus I do not find evidence of asymmetry. Chapter 2 studies the method of instrumental variables in set-identified models. I develop a proxy structural vector autoregression in which prior information from both theory and the empirical literature is incorporated about signs and magnitudes of certain parameters and equilibrium impacts. I use my method to investigate the relevance and validity of three popular instruments for monetary policy shocks, developed by Romer and Romer (2004), Sims and Zha (2006), and Smets and Wouters (2007). I find that all of them are strongly relevant but only that of Smets and Wouters is valid. Furthermore, the empirical analysis demonstrates that my framework can combine information from a relevant and valid instrument with prior information about sign restrictions to improve inference about structural impulse-response functions. Chapter 3 develops new methods to study dynamic causal effects in a data-rich environment. Current development in high-dimensional statistics fails to address the main interest of economists: causal inference with credible assumptions. I first review the literature on high-dimensional linear regression models and dynamic factor models. Then, I develop several new Bayesian numerical algorithms that combine the techniques in high-dimensional statistics with recent advances in dynamic causal inference. In particular, I discuss how to make causal statements from a high-dimensional structural model when researchers have doubts about identifying assumptions. Finally, I extend those algorithms to the case of Markov-switching models to accommodate nonlinearities in economic time series.
Download or read book Statistical Inference for High Dimensional Models written by Shijie Cui and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Statistical inference under high dimensional modelings has attracted much attention due to its wide applications in many fields. In this dissertation, I propose new methods for statistical inference in high dimensional models from three aspects: inference in high dimensional semiparametric models, inference in high dimensional matrix-valued data, and inference in high dimensional measurement error misspecified models. The first project studied statistical inference in high dimensional partially linear single index models. Firstly a profile partial penalized least squares estimator for parameter estimates for the model is proposed, and its asymptotic properties are given. Then an F-type test statistic for testing the parametric components is proposed, and its theoretical properties are established. I then propose a new test for the specification testing problem of the nonparametric components. Finally, simulation studies and empirical analysis of a real-world data set are conducted to illustrate the performance of the proposed testing procedure. The second project proposes new testing procedures in high dimensional matrix-valued data. Rank is an essential attribute for a matrix. A new type of statistic is proposed, which can make inferences on the rank of the matrix-valued data. I firstly give the theoretical property of its oracle version. To overcome the problem of empirical error accumulation, a new type of sparse SVD method is proposed, and its theoretical properties are given. Based on the newly proposed sparse SVD method, I provide a sample version statistic. Theoretical properties of this sample version statistic are given. Simulation studies and two applications to surveillance video data are provided to illustrate the performance of our newly proposed method. The third project proposes a new testing method in misspecified measurement error models. The testing method can work when there is potential model misspecification and measurement error in the model. Firstly its property is studied under the low dimensional setting. Then I develop it to the high dimensional setting. Further, I propose a method that can be adaptive to the sparsity level of the true parameters under the high dimensional setting. Simulation studies and one application to a clinical trial data set are given.
