Template-Type: ReDIF-Paper 1.0 Author-Name: Florian HUber Author-Name-First: Florian Author-Name-Last: HUber Author-Workplace-Name: University of Salzburg Author-Name: Gary Koop Author-Name-First: Gary Author-Name-Last: Koop Author-Workplace-Name: University of Strathclyde Author-Name: Michael Pfarrhoffer Author-Name-First: Michael Author-Name-Last: Pfarrhoffer Author-Workplace-Name: University of Salzburg Title: Bayesian Inference in High-Dimensional Time-varying Parameter Models using Integrated Rotated Gaussian Approximations Abstract: Researchers increasingly wish to estimate time-varying parameter (TVP) regressions which involve a large number of explanatory variables. Including prior information to mitigate over-parameterization concerns has led to many using Bayesian methods. However, Bayesian Markov Chain Monte Carlo (MCMC) methods can be very computationally demanding. In this paper, we develop computationally efficient Bayesian methods for estimating TVP models using an integrated rotated Gaussian approximation (IRGA). This exploits the fact that whereas constant coefficients on regressors are often important, most of the TVPs are often unimportant. Since Gaussian distributions are invariant to rotations we can split the the posterior into two parts: one involving the constant coefficients, the other involving the TVPs. Approximate methods are used on the latter and, conditional on these, the former are estimated with precision using MCMC methods. In empirical exercises involving artificial data and a large macroeconomic data set, we show the accuracy and computational bene ts of IRGA methods. Length: pages Creation-Date: Revision-Date: Publication-Status: Number: 2304 Classification-JEL: C11, C30, E3, D31 Keywords: Time-varying, parameter regression, Bayesian, Gaussian approximation, macroeconomic forecasting Handle: RePEc:str:wpaper:2304