arXiv Statistics ML By Hongqi Chen, Chengwang Liao, Ziwei Mei, Zhentao Shi

Cointegrated Regressors: Where Folded Concave Penalties Go Beyond LASSO

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The paper discusses the limitations of LASSO in high‑dimensional regression models when cointegrated regressors are present, noting that the convex penalty can overly shrink their coefficients and lead to inconsistent estimation. It proposes using folded concave penalties (FCP), such as SCAD and MCP, to overcome this issue, establishing both local and global oracle properties for the penalized regression. Simulation results and an application to euro area unemployment forecasting demonstrate that FCP improves variable selection and out‑of‑sample prediction compared to LASSO.

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