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Generalized Automatic Least Squares: Efficiency Gains from Misspecified Heteroscedasticity Models

Bulat Gafarov

arXiv 14 Apr 2023 · Econometrics

arXiv:2304.07331 · PDF · DOI · OpenAlex · Extracted main text

Abstract

It is well known that in the presence of heteroscedasticity ordinary least squares estimator is not efficient. I propose a generalized automatic least squares estimator (GALS) that makes partial correction of heteroscedasticity based on a (potentially) misspecified model without a pretest. Such an estimator is guaranteed to be at least as efficient as either OLS or WLS but can provide some asymptotic efficiency gains over OLS if the misspecified model is approximately correct. If the heteroscedasticity model is correct, the proposed estimator achieves full asymptotic efficiency. The idea is to frame moment conditions corresponding to OLS and WLS squares based on miss-specified heteroscedasticity as a joint generalized method of moments estimation problem. The resulting optimal GMM estimator is equivalent to a feasible GLS with estimated weight matrix. I also propose an optimal GMM variance-covariance estimator for GALS to account for any remaining heteroscedasticity in the residuals.

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Most heavily cited references

The works this paper leans on most, across its whole bibliography — not restricted to papers in our corpus. Ranked by composite intensity, which combines how often a work is mentioned, how many sections mention it, and how much of that falls in the main text rather than the appendix.

ReferenceIntensityMentionsSectionsMain text
1Romano, J. P. and M. Wolf (2017) Resurrecting weighted least squares0.51121100%
2Cragg, J. G (1983) More efficient estimation in the presence of heteroscedasticity of unknown form0.40511100%
3Hall, A. R (2004) Generalized method of moments0.40511100%
4Im, K. S. and P. Schmidt (2008) More efficient estimation under non-normality when higher moments do not depend on the regressors, using residual augmented leas…0.40511100%
5Lu, T.-T. and S.-H. Shiou (2002) Inverses of 2$$ 2 block matrices0.40511100%
6White, H (1980) A heteroskedasticity-consistent covariance matrix estimator and a direct test for heteroskedasticity0.40511100%
7Wooldridge, J. M (2019) Introductory Econometrics: A Modern Approach0.40511100%

Showing the top 7 of 7 scored citations.