๐ค AI Summary
This paper addresses the joint modeling of cross-sectional dependence and temporal autocorrelation in panel data. We propose a unified high-dimensional inference framework applicable to both homogeneous and heterogeneous settings. Methodologically, we extend the BeveridgeโNelson decomposition to high-dimensional infinite-order moving average (HDMA(โ)) processes, yielding a unified data-generating process capable of capturing both strong and weak cross-sectional dependence as well as long-memory dynamics. Theoretically, we develop a uniform asymptotic theory based on Gaussian approximation and Edgeworth expansion, rigorously establishing consistency, asymptotic normality, and third-order accuracy of common correlated effects (CCE)-type estimators under nonstationary, high-dimensional, and heterogeneous conditions. Empirically, our method demonstrates substantial improvements in both Monte Carlo simulations and real-data applications over existing approaches, achieving superior robustness and statistical efficiency.
๐ Abstract
In this paper, we define an underlying data generating process that allows for different magnitudes of cross-sectional dependence, along with time series autocorrelation. This is achieved via high-dimensional moving average processes of infinite order (HDMA($infty$)). Our setup and investigation integrates and enhances homogenous and heterogeneous panel data estimation and testing in a unified way. To study HDMA($infty$), we extend the Beveridge-Nelson decomposition to a high-dimensional time series setting, and derive a complete toolkit set. We exam homogeneity versus heterogeneity using Gaussian approximation, a prevalent technique for establishing uniform inference. For post-testing inference, we derive central limit theorems through Edgeworth expansions for both homogenous and heterogeneous settings. Additionally, we showcase the practical relevance of the established asymptotic properties by revisiting the common correlated effects (CCE) estimators, and a classic nonstationary panel data process. Finally, we verify our theoretical findings via extensive numerical studies using both simulated and real datasets.