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The Dantzig selector: Statistical estimation when p is much larger than n

2005/06/05 by Emmanuel J. Candès, Emmanuel Candes, Terence Tao +2 · 183 citations
Computer Science · Engineering · Mathematics · Physics and Astronomy · #Combinatorics #Estimator #Geometry #Mathematics #Quantum Information and Cryptography #Quantum Mechanics and Applications #Random Matrices and Applications #Scalar (mathematics) #Sparse and Compressive Sensing Techniques #Statistical Mechanics and Entropy #Statistical Methods and Inference #Statistics #math.ST #msc:62C05 #msc:62G05 #msc:94A08 #msc:94A12 #stat.TH

paper · pdf · doi:10.1214/009053606000001523

published in The Annals of Statistics 35(6), 83-84 (Institute of Mathematical Statistics) · This paper discussed in: [arXiv:0803.3124], [arXiv:0803.3126], [arXiv:0803.3127], [arXiv:0803.3130], [arXiv:0803.3134], [arXiv:0803.3135]. Rejoinder in [arXiv:0803.3136]. Published in at http://dx.doi.org/10.1214/009053606000001523 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org)

openalex publication_date 2007/12/01 · arxiv created 2008/03/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

In many important statistical applications, the number of variables or parameters p is much larger than the number of observations n. Suppose then that we have observations y=Xβ+z, where β∈Rp is a parameter vector of interest, X is a data matrix with possibly far fewer rows than columns, n≪p, and the zi’s are i.i.d. N(0, σ2). Is it possible to estimate β reliably based on the noisy data y? To estimate β, we introduce a new estimator—we call it the Dantzig selector—which is a solution to the ℓ1-regularization problem min_β\inRp‖β‖_ℓ1\quadsubject to ‖X*r‖_ℓ≤(1+t-1)√(2log p)⋅σ, where r is the residual vector y−Xβ̃ and t is a positive scalar. We show that if X obeys a uniform uncertainty principle (with unit-normed columns) and if the true parameter vector β is sufficiently sparse (which here roughly guarantees that the model is identifiable), then with very large probability, ‖β̂−β‖ℓ22≤C2⋅2log p⋅(σ2+∑imin(βi2, σ2)). Our results are nonasymptotic and we give values for the constant C. Even though n may be much smaller than p, our estimator achieves a loss within a logarithmic factor of the ideal mean squared error one would achieve with an oracle which would supply perfect information about which coordinates are nonzero, and which were above the noise level. In multivariate regression and from a model selection viewpoint, our result says that it is possible nearly to select the best subset of variables by solving a very simple convex program, which, in fact, can easily be recast as a convenient linear program (LP).

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