Abstract
We consider the estimation of the mean of a multivariate normal distribution with known variance. Most studies consider the risk of competing estimators, that is the trace of the mean squared error matrix. In contrast we consider the whole mean squared error matrix, in particular its eigenvalues. We prove that there are only two distinct eigenvalues and apply our findings to the James–Stein and the Thompson class of estimators. It turns out that the famous Stein paradox is no longer a paradox when we consider the whole mean squared error matrix rather than only its trace.
Original language | English |
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Pages (from-to) | S239-S266 |
Number of pages | 28 |
Journal | Journal of Quantitative Economics |
Volume | 19 |
Issue number | Suppl 1 |
Early online date | 18 Nov 2021 |
DOIs | |
Publication status | Published - Dec 2021 |
Bibliographical note
Funding Information:We are grateful to the Guest Editors of this special issue and to two referees for comments and suggestions. We are especially grateful to Akio Namba for providing the key to proving Proposition . Without his help this result would have remained a conjecture. Giuseppe De Luca acknowledges financial support from the MIUR PRIN PRJ-0324.
Publisher Copyright:
© 2021, The Author(s), under exclusive licence to The Indian Econometric Society.
Keywords
- C13
- C51
- Dominance
- James–Stein
- Shrinkage