English

Non-minimaxity of debiased shrinkage estimators

Statistics Theory 2023-06-08 v1 Statistics Theory

Abstract

We consider the estimation of the pp-variate normal mean of XNp(θ,I)X\sim N_p(\theta,I) under the quadratic loss function. We investigate the decision theoretic properties of debiased shrinkage estimator, the estimator which shrinks towards the origin for smaller x2\|x\|^2 and which is exactly equal to the unbiased estimator XX for larger x2\|x\|^2. Such debiased shrinkage estimator seems superior to the unbiased estimator XX, which implies minimaxity. However we show that it is not minimax under mild conditions.

Keywords

Cite

@article{arxiv.2306.04232,
  title  = {Non-minimaxity of debiased shrinkage estimators},
  author = {Yuzo Maruyama and Akimichi Takemura},
  journal= {arXiv preprint arXiv:2306.04232},
  year   = {2023}
}