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Singapore Management University

Research Collection School Of Economics

Series

2013

Spatial dependence

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Heteroskedasticity And Non-Normality Robust Lm Tests Of Spatial Dependence, Badi H. Baltagi, Zhenlin Yang Sep 2013

Heteroskedasticity And Non-Normality Robust Lm Tests Of Spatial Dependence, Badi H. Baltagi, Zhenlin Yang

Research Collection School Of Economics

The standard LM tests for spatial dependence in linear and panel regressions are derived under the normality and homoskedasticity assumptions of the regression disturbances. Hence, they may not be robust against non-normality or heteroskedasticity of the disturbances. Following Born and Breitung (2011), we introduce general methods to modify the standard LM tests so that they become robust against heteroskedasticity and non-normality. The idea behind the robustification is to decompose the concentrated score function into a sum of uncorrelated terms so that the outer product of gradient (OPG) can be used to estimate its variance. We also provide methods for improving …


Lm Tests Of Spatial Dependence Based On Bootstrap Critical Values, Zhenlin Yang May 2013

Lm Tests Of Spatial Dependence Based On Bootstrap Critical Values, Zhenlin Yang

Research Collection School Of Economics

To test the existence of spatial dependence in an econometric model, a convenient test is the Lagrange Multiplier (LM) test. However, evidence shows that, in finite samples, the LM test referring to asymptotic critical values may suffer from the problems of size distortion and low power, which become worse with a denser spatial weight matrix. In this paper, residual-based bootstrap methods are introduced for asymptotically refined approximations to the finite sample critical values of the LM statistics. Conditions for their validity are clearly laid out and formal justifications are given in general, and in details under several popular spatial LM …


Non-Normality And Heteroscedasticity Robust Lm Tests Of Spatial Dependence, Badi H. Baltagi, Zhenlin Yang Jan 2013

Non-Normality And Heteroscedasticity Robust Lm Tests Of Spatial Dependence, Badi H. Baltagi, Zhenlin Yang

Research Collection School Of Economics

The standard LM tests for spatial dependence in linear and panel regressions are derived under the normality and homoskedasticity assumptions of the regression disturbances. Hence, they may not be robust against non-normality or heteroskedasticity of the disturbances. Following Born and Breitung (2011), we introduce general methods to modify the standard LM tests so that they become robust against heteroskedasticity and non-normality. The idea behind the robustification is to decompose the concentrated score function into a sum of uncorrelated terms so that the outer product of gradient (OPG) can be used to estimate its variance. We also provide methods for improving …