Arbeitspapier
A lava attack on the recovery of sums of dense and sparse signals
Common high-dimensional methods for prediction rely on having either a sparse signal model, a model in which most parameters are zero and there are a small number of non-zero parameters that are large in magnitude, or a dense signal model, a model with no large parameters and very many small non-zero parameters. We consider a generalization of these two basic models, termed here a "sparse + dense" model, in which the signal is given by the sum of a sparse signal and a dense signal. Such a structure poses problems for traditional sparse estimators, such as the lasso, and for traditional dense estimation methods, such as ridge estimation. We propose a new penalization-based method, called lava, which is computationally efficient. With suitable choices of penalty parameters, the proposed method strictly dominates both lasso and ridge. We derive analytic expressions for the finite-sample risk function of the lava estimator in the Gaussian sequence model. We also provide a deviation bound for the prediction risk in the Gaussian regression model with fixed design. In both cases, we provide Stein's unbiased estimator for lava's prediction risk. A simulation example compares the performance of lava to lasso, ridge, and elastic net in a regression example using data-dependent penalty parameters and illustrates lava's improved performance relative to these benchmarks.
- Language
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Englisch
- Bibliographic citation
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Series: cemmap working paper ; No. CWP56/15
- Classification
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Wirtschaft
- Subject
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high-dimensional models
penalization
shrinkage
non-sparse signal recovery
- Event
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Geistige Schöpfung
- (who)
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Chernozhukov, Victor
Hansen, Christian
Liao, Yuan
- Event
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Veröffentlichung
- (who)
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Centre for Microdata Methods and Practice (cemmap)
- (where)
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London
- (when)
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2015
- DOI
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doi:10.1920/wp.cem.2015.5615
- Handle
- Last update
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10.03.2025, 11:43 AM CET
Data provider
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Object type
- Arbeitspapier
Associated
- Chernozhukov, Victor
- Hansen, Christian
- Liao, Yuan
- Centre for Microdata Methods and Practice (cemmap)
Time of origin
- 2015