Publication Type
Journal Article
Version
publishedVersion
Publication Date
10-2023
Abstract
Functional coefficient (FC) regressions allow for systematic flexibility in the responsiveness of a dependent variable to movements in the regressors, making them attractive in applications where marginal effects may depend on covariates. Such models are commonly estimated by local kernel regression methods. This paper explores situations where responsiveness to covariates is locally flat or fixed. The paper develops new asymptotics that take account of shape characteristics of the function in the locality of the point of estimation. Both stationary and integrated regressor cases are examined. The limit theory of FC kernel regression is shown to depend intimately on functional shape in ways that affect rates of convergence, optimal bandwidth selection, estimation, and inference. In FC cointegrating regression, flat behavior materially changes the limit distribution by introducing the shape characteristics of the function into the limiting distribution through variance as well as centering. In the boundary case where the number of zero derivatives tends to infinity, near parametric rates of convergence apply in stationary and nonstationary cases. Implications for inference are discussed and a feasible pre-test inference procedure is proposed that takes unknown potential flatness into consideration and provides a practical approach to inference.
Discipline
Econometrics | Economic Theory
Research Areas
Econometrics
Publication
Econometric Theory
Volume
39
Issue
5
First Page
900
Last Page
949
ISSN
0266-4666
Identifier
10.1017/S0266466622000287
Publisher
Cambridge University Press
Citation
PHILLIPS, Peter C. B. and WANG, Ying.
Limit theory for locally flat functional coefficient regression. (2023). Econometric Theory. 39, (5), 900-949.
Available at: https://ink.library.smu.edu.sg/soe_research/2782
Copyright Owner and License
Authors CC-BY
Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.
Additional URL
https://doi.org/10.1017/S0266466622000287