Abstract
In this paper, we summarize results on convergence rates of various kernel based non- and semiparametric estimators, focusing on the impact of insufficient distributional smoothness, possibly unknown smoothness and even non-existence of density. In the presence of a possible lack of smoothness and the uncertainty about smoothness, methods of safeguarding against this uncertainty are surveyed with emphasis on nonconvex model averaging. This approach can be implemented via a combined estimator that selects weights based on minimizing the asymptotic mean squared error. In order to evaluate the finite sample performance of these and similar estimators we argue that it is important to account for possible lack of smoothness.
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23 December 2021
The original online published version of the article as been updated due to Open access cancellation.
23 December 2021
A Correction to this paper has been published: https://doi.org/10.1007/s40953-021-00280-w
Notes
As a referee pointed out, the estimation of the degree of smoothness bears similarity to the test for smoothness in Mukherjee et al. (2016) in the context of adaptive Lepski estimation of nonlinear functionals of density.
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Acknowledgements
We thank an anonymous referee for valuable comments. This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC)
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Natural Sciences and Engineering Research Council of Canada (NSERC).
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Kotlyarova, Y., Schafgans, M.M.A. & Zinde-Walsh, V. Rates of Expansions for Functional Estimators. J. Quant. Econ. 19 (Suppl 1), 121–139 (2021). https://doi.org/10.1007/s40953-021-00266-8
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DOI: https://doi.org/10.1007/s40953-021-00266-8
Keywords
- Nonparametric estimation
- Kernel based estimation
- Model averaging
- Combined estimator
- Convergence rates
- Degree of smoothness