I'm really confused about Breusch and Pagan Lagrangian multiplier test for random effects.
The command in stata is xttest0.
Some say it is a test to choose between random and fixed effects and simple OLS
refer to slide NO 32 http://www.princeton.edu/~otorres/Panel101.pdf
….
And some say it is a test for heteroskedasticity in random-effects model.
look at figure 2 https://www.projectguru.in/panel-data-regression-random-effect-model-stata/
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I have searched all the web to find how to do heteroskedasticity test for random effects model in Stata, but simply there is no clear answer that is agreed by all.
Best Answer
The second site you cite looks a bit suspicious: It mentions normality of the data set but I feel like the author wanted to say normality of residuals.
Please note there are two papers by Breusch/Pagan with a "Breusch-Pagan test":
The first is implemented by
xttest0
in Stata (and in R inplmtest
of packageplm
). The second in Stata byhettest
(and in R inbptest
of packagelmtest
) and - I believe - cannot readily be applied to panel models.The 2nd webpage seems to confuse both tests/use cases.