Weak identification of long memory with implications for inference

This paper explores weak identification issues arising in commonly used models of economic and financial time series. Two highly popular configurations are shown to be asymptotically observationally equivalent: one with long memory and weak autoregressive dynamics, the other with antipersistent shoc...

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Bibliographic Details
Main Authors: LI, Jia, PHILLIPS, Peter C. B., SHI, Shuping, Jun YU
Format: text
Language:English
Published: Institutional Knowledge at Singapore Management University 2022
Subjects:
Online Access:https://ink.library.smu.edu.sg/soe_research/2616
https://ink.library.smu.edu.sg/context/soe_research/article/3615/viewcontent/WeakIDFAR.pdf
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Institution: Singapore Management University
Language: English
Description
Summary:This paper explores weak identification issues arising in commonly used models of economic and financial time series. Two highly popular configurations are shown to be asymptotically observationally equivalent: one with long memory and weak autoregressive dynamics, the other with antipersistent shocks and a near-unit autoregressive root. We develop a data-driven semiparametric and identification-robust approach to inference that reveals such ambiguities and documents the prevalence of weak identification in many realized volatility and trading volume series. The identification-robust empirical evidence generally favors long memory dynamics in volatility and volume, a conclusion that is corroborated using social-media news flow data.