Journal ArticleOperations Research · March 1, 2024
We consider a platform that serves (observable) agents, who belong to a larger network that also includes additional agents who are not served by the platform. We refer to the latter group of agents as latent agents. Associated with each agent are the agen ...
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Journal ArticleAnnals of Statistics · February 1, 2023
We propose a generalization of the linear panel quantile regression model to accommodate both sparse and dense parts: sparse means that while the number of covariates available is large, potentially only a much smaller number of them have a nonzero impact ...
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Journal ArticleJournal of Econometrics · May 1, 2022
High-dimensional linear models with endogenous variables play an increasingly important role in the recent econometric literature. In this work, we allow for models with many endogenous variables and make use of many instrumental variables to achieve ident ...
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Journal ArticleJournal of Econometrics · November 1, 2019
Quantile regression (QR) is a principal regression method for analyzing the impact of covariates on outcomes. The impact is described by the conditional quantile function and its functionals. In this paper we develop the nonparametric QR-series framework, ...
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Journal ArticleJournal of the American Statistical Association · April 3, 2019
This work proposes new inference methods for a regression coefficient of interest in a (heterogenous) quantile regression model. We consider a high-dimensional model where the number of regressors potentially exceeds the sample size but a subset of them su ...
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Journal ArticleAnnals of statistics · December 2018
In this paper, we develop procedures to construct simultaneous confidence bands for p ˜ potentially infinite-dimensional parameters after model selection for general moment condition models where p ˜ is potentially much larger than the sample size of a ...
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Journal ArticleManagement Science · December 1, 2017
We study the effect of multilateral private information on the efficiency of markets where capacity-constrained upstream agents supply a resource to downstream entities facing uncertain end-demands. We analyze two models: a "pooling system," in which a sin ...
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Journal ArticleJournal of the Royal Statistical Society. Series B: Statistical Methodology · June 1, 2017
We consider the linear regression model with observation error in the design. In this setting, we allow the number of covariates to be much larger than the sample size. Several new estimation methods have been recently introduced for this model. Indeed, th ...
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Journal ArticleOperations Research · May 1, 2017
A revenue-maximizing monopolist is selling a single indivisible good to buyers who face a loss if any of its rival buyers obtain it. The rivalry is modeled through a network, an arc between a pair of buyers indicates that a buyer considers another buyer it ...
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Journal ArticleAnnals of Statistics · February 1, 2017
We study a variable length Markov chain model associated with a group of stationary processes that share the same context tree but each process has potentially different conditional probabilities. We propose a new model selection and estimation method whic ...
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Journal ArticleEconometrica · January 1, 2017
In this paper, we provide efficient estimators and honest confidence bands for a variety of treatment effects including local average (LATE) and local quantile treatment effects (LQTE) in data-rich environments. We can handle very many control variables, e ...
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Chapter · January 1, 2017
High-dimensional models arise from the need for practitioners to improve the accuracy and validity of current models and to handle the increasing availability of data. Large models can arise from using a very flexible specification with many parameters whe ...
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Journal ArticleJournal of Business and Economic Statistics · October 1, 2016
This article considers generalized linear models in the presence of many controls. We lay out a general methodology to estimate an effect of interest based on the construction of an instrument that immunizes against model selection mistakes and apply it to ...
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Journal ArticleJournal of Business and Economic Statistics · October 1, 2016
We consider estimation and inference in panel data models with additive unobserved individual specific heterogeneity in a high-dimensional setting. The setting allows the number of time-varying regressors to be larger than the sample size. To make informat ...
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Journal ArticleElectronic Journal of Statistics · January 1, 2016
Several new estimation methods have been recently proposed for the linear regression model with observation errors in the design. Different assumptions on the data generating process have motivated different estimators and analysis. In particular, the lite ...
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Journal ArticleR Journal · January 1, 2016
The R package quantreg.nonpar implements nonparametric quantile regression methods to estimate and make inference on partially linear quantile models. quantreg.nonpar obtains point estimates of the conditional quantile function and its derivatives based on ...
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Journal ArticleJournal of Econometrics · June 1, 2015
In econometric applications it is common that the exact form of a conditional expectation is unknown and having flexible functional forms can lead to improvements over a pre-specified functional form, especially if they nest some successful parametric econ ...
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Journal ArticleBiometrika · March 1, 2015
We develop uniformly valid confidence regions for regression coefficients in a highdimensional sparse median regression model with homoscedastic errors. Our methods are based on amoment equation that is immunized against nonregular estimation of the nuisan ...
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ConferenceJournal of Machine Learning Research · January 1, 2015
We consider the problem of optimizing an approximately convex function over a bounded convex set in Rn using only function evaluations. The problem is reduced to sampling from an approximately log-concave distribution using the Hit-and-Run method, which is ...
Cite
Journal ArticleOperations Research · March 1, 2024
We consider a platform that serves (observable) agents, who belong to a larger network that also includes additional agents who are not served by the platform. We refer to the latter group of agents as latent agents. Associated with each agent are the agen ...
Full textCite
Journal ArticleAnnals of Statistics · February 1, 2023
We propose a generalization of the linear panel quantile regression model to accommodate both sparse and dense parts: sparse means that while the number of covariates available is large, potentially only a much smaller number of them have a nonzero impact ...
Full textCite
Journal ArticleJournal of Econometrics · May 1, 2022
High-dimensional linear models with endogenous variables play an increasingly important role in the recent econometric literature. In this work, we allow for models with many endogenous variables and make use of many instrumental variables to achieve ident ...
Full textCite
Journal ArticleJournal of Econometrics · November 1, 2019
Quantile regression (QR) is a principal regression method for analyzing the impact of covariates on outcomes. The impact is described by the conditional quantile function and its functionals. In this paper we develop the nonparametric QR-series framework, ...
Full textCite
Journal ArticleJournal of the American Statistical Association · April 3, 2019
This work proposes new inference methods for a regression coefficient of interest in a (heterogenous) quantile regression model. We consider a high-dimensional model where the number of regressors potentially exceeds the sample size but a subset of them su ...
Full textCite
Journal ArticleAnnals of statistics · December 2018
In this paper, we develop procedures to construct simultaneous confidence bands for p ˜ potentially infinite-dimensional parameters after model selection for general moment condition models where p ˜ is potentially much larger than the sample size of a ...
Full textCite
Journal ArticleManagement Science · December 1, 2017
We study the effect of multilateral private information on the efficiency of markets where capacity-constrained upstream agents supply a resource to downstream entities facing uncertain end-demands. We analyze two models: a "pooling system," in which a sin ...
Full textCite
Journal ArticleJournal of the Royal Statistical Society. Series B: Statistical Methodology · June 1, 2017
We consider the linear regression model with observation error in the design. In this setting, we allow the number of covariates to be much larger than the sample size. Several new estimation methods have been recently introduced for this model. Indeed, th ...
Full textCite
Journal ArticleOperations Research · May 1, 2017
A revenue-maximizing monopolist is selling a single indivisible good to buyers who face a loss if any of its rival buyers obtain it. The rivalry is modeled through a network, an arc between a pair of buyers indicates that a buyer considers another buyer it ...
Full textCite
Journal ArticleAnnals of Statistics · February 1, 2017
We study a variable length Markov chain model associated with a group of stationary processes that share the same context tree but each process has potentially different conditional probabilities. We propose a new model selection and estimation method whic ...
Full textCite
Journal ArticleEconometrica · January 1, 2017
In this paper, we provide efficient estimators and honest confidence bands for a variety of treatment effects including local average (LATE) and local quantile treatment effects (LQTE) in data-rich environments. We can handle very many control variables, e ...
Full textCite
Chapter · January 1, 2017
High-dimensional models arise from the need for practitioners to improve the accuracy and validity of current models and to handle the increasing availability of data. Large models can arise from using a very flexible specification with many parameters whe ...
Full textCite
Journal ArticleJournal of Business and Economic Statistics · October 1, 2016
This article considers generalized linear models in the presence of many controls. We lay out a general methodology to estimate an effect of interest based on the construction of an instrument that immunizes against model selection mistakes and apply it to ...
Full textCite
Journal ArticleJournal of Business and Economic Statistics · October 1, 2016
We consider estimation and inference in panel data models with additive unobserved individual specific heterogeneity in a high-dimensional setting. The setting allows the number of time-varying regressors to be larger than the sample size. To make informat ...
Full textCite
Journal ArticleElectronic Journal of Statistics · January 1, 2016
Several new estimation methods have been recently proposed for the linear regression model with observation errors in the design. Different assumptions on the data generating process have motivated different estimators and analysis. In particular, the lite ...
Full textCite
Journal ArticleR Journal · January 1, 2016
The R package quantreg.nonpar implements nonparametric quantile regression methods to estimate and make inference on partially linear quantile models. quantreg.nonpar obtains point estimates of the conditional quantile function and its derivatives based on ...
Full textCite
Journal ArticleJournal of Econometrics · June 1, 2015
In econometric applications it is common that the exact form of a conditional expectation is unknown and having flexible functional forms can lead to improvements over a pre-specified functional form, especially if they nest some successful parametric econ ...
Full textCite
Journal ArticleBiometrika · March 1, 2015
We develop uniformly valid confidence regions for regression coefficients in a highdimensional sparse median regression model with homoscedastic errors. Our methods are based on amoment equation that is immunized against nonregular estimation of the nuisan ...
Full textCite
ConferenceJournal of Machine Learning Research · January 1, 2015
We consider the problem of optimizing an approximately convex function over a bounded convex set in Rn using only function evaluations. The problem is reduced to sampling from an approximately log-concave distribution using the Hit-and-Run method, which is ...
Cite
Journal ArticleEconometrics Journal · January 1, 2014
Summary: In this paper, we study the large-sample properties of the posterior-based inference in the curved exponential family under increasing dimensions. The curved structure arises from the imposition of various restrictions on the model, such as moment ...
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Journal ArticleAnnals of Statistics · January 1, 2014
We propose a self-tuning √ Lasso method that simultaneously resolves three important practical problems in high-dimensional regression analysis, namely it handles the unknown scale, heteroscedasticity and (drastic) non- Gaussianity of the noise. In additio ...
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Journal ArticleBernoulli · January 1, 2013
In this article we study post-model selection estimators that apply ordinary least squares (OLS) to the model selected by first-step penalized estimators, typically Lasso. It is well known that Lasso can estimate the nonparametric regression function at ne ...
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Journal ArticleReview of Economic Studies · January 1, 2013
We propose robust methods for inference about the effect of a treatment variable on a scalar outcome in the presence of very many regressors in a model with possibly non-Gaussian and heteroscedastic disturbances. We allow for the number of regressors to be ...
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Journal ArticleEconometrica · November 1, 2012
We develop results for the use of Lasso and post-Lasso methods to form first-stage predictions and estimate optimal instruments in linear instrumental variables (IV) models with many instruments, p. Our results apply even when p is much larger than the sam ...
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Journal ArticleMarketing Science · July 1, 2012
Each year in the postsecondary education industry, schools offer admission to nearly 3 million new students and scholarships totaling nearly $100 billion. This is a large, understudied targeted marketing and price discrimination problem. This problem falls ...
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Journal ArticleBiometrika · December 1, 2011
We propose a pivotal method for estimating high-dimensional sparse linear regression models, where the overall number of regressors p is large, possibly much larger than n, but only s regressors are significant. The method is a modification of the lasso, c ...
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Journal ArticleAnnals of Statistics · February 1, 2011
We consider median regression and, more generally, a possibly infinite collection of quantile regressions in high-dimensional sparse models. In these models, the number of regressors p is very large, possibly larger than the sample size n, but only at most ...
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Journal Article · January 1, 2011
Introduction We consider linear, high-dimensional sparse (HDS) regression models in econometrics. The HDS regression model allows for a large number of regressors, p, which is possibly much larger than the sample size, n, but imposes that the model is spar ...
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Journal ArticleOperations Research · July 1, 2010
Multidimensional mechanism design problems have proven difficult to solve by extending techniques from the onedimensional case. This paper considers mechanism design problems with multidimensional types when the seller's cost function is not separable acro ...
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Journal ArticleMathematical Programming · September 1, 2009
Lagrangian relaxation is a popular technique to solve difficult optimization problems. However, the applicability of this technique depends on having a relatively low number of hard constraints to dualize. When there are many hard constraints, it may be pr ...
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Journal ArticleMathematics of Operations Research · August 1, 2009
The classical perceptron algorithm is an elementary row-action/relaxation algorithm for solving a homogeneous linear inequality system Ax > 0. A natural condition measure associated with this algorithm is the Euclidean width t of the cone of feasible solut ...
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Journal ArticleAnnals of Statistics · August 1, 2009
In this paper we examine the implications of the statistical large sample theory for the computational complexity of Bayesian and quasi-Bayesian estimation carried out using Metropolis random walks. Our analysis is motivated by the Laplace-Bernstein-Von Mi ...
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Journal ArticleMathematical Programming · June 1, 2009
For a conic linear system of the form Ax K, K a convex cone, several condition measures have been extensively studied in the last dozen years. Among these, Renegar's condition number {\mathcal{C}}(A) is arguably the most prominent for its relation to data ...
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Journal ArticleMathematical Programming · May 1, 2009
In this paper we study the homogeneous conic system F: Ax = 0, x in C setminus 0 . We choose a point in ∫ C that serves as a normalizer and consider computational properties of the normalized system Fs : Ax = 0, bar s-T x = 1, x ∈ C . We show that the comp ...
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Journal ArticleSIAM Journal on Optimization · December 1, 2008
We study the second-order feasibility cone F = {y ∈ ℝn : ∥ My ∥ ≤ gTy} for given data (M,g). We construct a new representation for this cone and its dual based on the spectral decomposition of the matrix MTM - ggT. This representation is used to efficientl ...
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Journal ArticleAnnals of Statistics · October 1, 2008
In this paper we provide a provably convergent algorithm for the multivariate Gaussian Maximum Likelihood version of the Behrens-Fisher Problem. Our work builds upon a formulation of the log-likelihood function proposed by Buot and Richards [5]. Instead of ...
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Journal ArticleManagement Science · September 1, 2008
We take advantage of recent advances in optimization methods and computer hardware to identify globally optimal solutions of product line design problems that are too large for complete enumeration. We then use this guarantee of global optimality to benchm ...
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Journal ArticleMathematics of Operations Research · February 1, 2008
In this paper, we explore properties of a family of probability density functions, called norm-induced densities, defined as f t(x)={e -t||x||p/∫ Ke -t||y||pdy, x ∈ K 0, x ∉ K, where K is a n-dimensional convex set that contains the origin, parameters t > ...
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Journal ArticleMathematical Programming · January 1, 2008
We attempt a broad exploration of properties and connections between the symmetry function of a convex set S ⊂ ℝn and other arenas of convexity including convex functions, convex geometry, probability theory on convex sets, and computational complexity. Gi ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 2007
The classical perceptron algorithm is an elementary algorithm for solving a homogeneous linear inequality system Ax > 0, with many important applications in learning theory (e.g., [11,8]). A natural condition measure associated with this algorithm is the E ...
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Journal ArticleAnnals of Operations Research · April 1, 2003
We consider the inclusion of commitment of thermal generation units in the optimal management of the Brazilian power system. By means of Lagrangian relaxation we decompose the problem and obtain a nondifferentiable dual function that is separable. We solve ...
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