A Nonparametric Approach to Augmenting a Bayesian VAR with Nonlinear Factors

Fuente: arXiv
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Hauptverfasser: Clark, Todd, Huber, Florian, Koop, Gary
Format: Preprint
Veröffentlicht: 2025
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author Clark, Todd
Huber, Florian
Koop, Gary
author_facet Clark, Todd
Huber, Florian
Koop, Gary
contents This paper proposes a Vector Autoregression augmented with nonlinear factors that are modeled nonparametrically using regression trees. There are four main advantages of our model. First, modeling potential nonlinearities nonparametrically lessens the risk of mis-specification. Second, the use of factor methods ensures that departures from linearity are modeled parsimoniously. In particular, they exhibit functional pooling where a small number of nonlinear factors are used to model common nonlinearities across variables. Third, Bayesian computation using MCMC is straightforward even in very high dimensional models, allowing for efficient, equation by equation estimation, thus avoiding computational bottlenecks that arise in popular alternatives such as the time varying parameter VAR. Fourth, existing methods for identifying structural economic shocks in linear factor models can be adapted for the nonlinear case in a straightforward fashion using our model. Exercises involving artificial and macroeconomic data illustrate the properties of our model and its usefulness for forecasting and structural economic analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2508_13972
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Nonparametric Approach to Augmenting a Bayesian VAR with Nonlinear Factors
Clark, Todd
Huber, Florian
Koop, Gary
Econometrics
Methodology
This paper proposes a Vector Autoregression augmented with nonlinear factors that are modeled nonparametrically using regression trees. There are four main advantages of our model. First, modeling potential nonlinearities nonparametrically lessens the risk of mis-specification. Second, the use of factor methods ensures that departures from linearity are modeled parsimoniously. In particular, they exhibit functional pooling where a small number of nonlinear factors are used to model common nonlinearities across variables. Third, Bayesian computation using MCMC is straightforward even in very high dimensional models, allowing for efficient, equation by equation estimation, thus avoiding computational bottlenecks that arise in popular alternatives such as the time varying parameter VAR. Fourth, existing methods for identifying structural economic shocks in linear factor models can be adapted for the nonlinear case in a straightforward fashion using our model. Exercises involving artificial and macroeconomic data illustrate the properties of our model and its usefulness for forecasting and structural economic analysis.
title A Nonparametric Approach to Augmenting a Bayesian VAR with Nonlinear Factors
topic Econometrics
Methodology
url https://arxiv.org/abs/2508.13972