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Re: st: RE: Hausman Test Problems


From   Muhammad Anees <aneesmkhattak@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: Hausman Test Problems
Date   Mon, 2 May 2011 15:56:05 +0500

Thanks, Mark, John and Eric for your all time guidance on the issue.
Let me review the paper and do more practice before concluding this
discussion. I would be discussing more questions if i had after the
review and practicing. Thanks again



On 2 May 2011 15:34, John Antonakis <John.Antonakis@unil.ch> wrote:
> Right; thanks for the clarification, Mark. Maybe I was not clear enough, but
> if one model is nested in the other, then one makes a restriction (that the
> L2 predictors do not correlate with the constant effect), which gives the
> overid interpretation. The reason why I talked about this is that I thought
> that Muhammad was thinking that he need to have instruments (where he said
> that he did not "pretest it for overidentification").
>
> BTW, the paper I cited below is a real eye opener because it show just how
> many restrictions are in these models (for those who are interested):
>
> Bollen, K. A.,&  Brand, J. E. (2010). A General Panel Model with Random and
> Fixed Effects A Structural Equations
> Approach. Social Forces, 89(1), 1-34.
>
> Best,
> J.
>
> __________________________________________
>
> Prof. John Antonakis
> Faculty of Business and Economics
> Department of Organizational Behavior
> University of Lausanne
> Internef #618
> CH-1015 Lausanne-Dorigny
> Switzerland
> Tel ++41 (0)21 692-3438
> Fax ++41 (0)21 692-3305
> http://www.hec.unil.ch/people/jantonakis
>
> Associate Editor
> The Leadership Quarterly
> __________________________________________
>
>
> On 02.05.2011 11:45, Schaffer, Mark E wrote:
>>
>> John, Muhammad,
>>
>> The test of fixed vs. random effects (also) has an overid test
>> interpretation.  The FE estimator uses the moment conditions
>> E(x_it*e_it)=0.  The RE estimator uses, in addition, the moment
>> conditions E(x_it*u_i)=0.  That's what makes it overidentified and an
>> overid test possible.
>>
>> There is a short discussion and some references in the xtoverid help
>> file.
>>
>> Cheers,
>> Mark
>>
>>> -----Original Message-----
>>> From: owner-statalist@hsphsun2.harvard.edu
>>> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of
>>> John Antonakis
>>> Sent: 02 May 2011 10:11
>>> To: statalist@hsphsun2.harvard.edu
>>> Subject: Re: st: RE: Hausman Test Problems
>>>
>>> You don't need to be overidentified to use xtoverid.  The
>>> command in fact tests a constraint that is made, which nests
>>> the random and fixed-effects models (i.e., the constraint
>>> that is made to the random effects model is that level 2
>>> regressors do not correate with uj).
>>>
>>> To get a better handle on what types of constraints are made
>>> in these types of models see:
>>>
>>> Bollen, K. A.,&  Brand, J. E. (2010). A General Panel Model
>>> with Random and Fixed Effects A Structural Equations
>>> Approach. Social Forces, 89(1), 1-34.
>>>
>>> HTH,
>>> John.
>>>
>>> __________________________________________
>>>
>>> Prof. John Antonakis
>>> Faculty of Business and Economics
>>> Department of Organizational Behavior
>>> University of Lausanne
>>> Internef #618
>>> CH-1015 Lausanne-Dorigny
>>> Switzerland
>>> Tel ++41 (0)21 692-3438
>>> Fax ++41 (0)21 692-3305
>>> http://www.hec.unil.ch/people/jantonakis
>>>
>>> Associate Editor
>>> The Leadership Quarterly
>>> __________________________________________
>>>
>>>
>>> On 02.05.2011 10:56, Muhammad Anees wrote:
>>>>
>>>> Thanks Eric!
>>>>
>>>> It did worked for me. I actually run the regressions without
>>>> pretesting it for any overidentification. Can I still follow any
>>>> procedure selecting one of the FE and RE using over
>>>
>>> identified panel
>>>>
>>>> data regressions.
>>>>
>>>> On 2 May 2011 12:44, DE SOUZA
>>>
>>> Eric<eric.de_souza@coleurope.eu>   wrote:
>>>>>
>>>>> The Hausman test for fixed vs  random is only valid under
>>>
>>> a strict set of assumptions. These assumptions are clearly
>>> not satisfied in your case .
>>>>>
>>>>> Use -xtoverid-. Download it from ssc: -ssc install
>>>
>>> xtoverid- and read the help file first.
>>>>>
>>>>> Eric de Souza
>>>>> College of Europe
>>>>> Brugge (Bruges), Belgium
>>>>> http://www.coleurope.eu
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: owner-statalist@hsphsun2.harvard.edu
>>>>> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of
>>>
>>> Muhammad
>>>>>
>>>>> Anees
>>>>> Sent: 02 May 2011 06:12
>>>>> To: statalist@hsphsun2.harvard.edu
>>>>> Subject: st: Hausman Test Problems
>>>>>
>>>>> Dear All!
>>>>>
>>>>> I have run a panel data regression and selection of the
>>>
>>> random effects or fixed effects using Hausman test. I do not
>>> know what is the actual problem with my results. Please could
>>> someone help. Why the result for my hausman command results
>>> in warning message?
>>>>>
>>>>> the complete results are below:
>>>>>
>>>>>
>>>>> . xtreg priceclose eps bookvalue, fe
>>>>>
>>>>> Fixed-effects (within) regression               Number of
>>>
>>> obs      =       850
>>>>>
>>>>> Group variable: id                              Number of
>>>
>>> groups   =       170
>>>>>
>>>>> R-sq:  within  = 0.1160                         Obs per
>>>
>>> group: min =         5
>>>>>
>>>>> between = 0.5266
>>>
>>> avg =       5.0
>>>>>
>>>>> overall = 0.4645
>>>
>>> max =         5
>>>>>
>>>>> F(2,678)           =     44.48
>>>>> corr(u_i, Xb)  = 0.4836                         Prob>   F
>>>
>>>         =    0.0000
>>>>>
>>>>> priceclose       Coef.   Std. Err.      t    P>t     [95%
>>>
>>> Conf. Interval]
>>>>>
>>>>> eps    .7770481   .1966364     3.95   0.000     .3909585
>>>
>>>  1.163138
>>>>>
>>>>> bookvalue    .8653121   .1577343     5.49   0.000
>>>
>>> .5556057    1.175018
>>>>>
>>>>> _cons    1.001173   .1176642     8.51   0.000     .7701434
>>>
>>>    1.232204
>>>>>
>>>>> sigma_u   3.5662704
>>>>> sigma_e   1.5953308
>>>>> rho   .83325562   (fraction of variance due to u_i)
>>>>>
>>>>> F test that all u_i=0:     F(169, 678) =    17.34
>>>
>>>   Prob>   F = 0.0000
>>>>>
>>>>> .
>>>>> . estimates store fe
>>>>>
>>>>> .
>>>>> . xtreg priceclose eps bookvalue, re
>>>>>
>>>>> Random-effects GLS regression                   Number of
>>>
>>> obs      =       850
>>>>>
>>>>> Group variable: id                              Number of
>>>
>>> groups   =       170
>>>>>
>>>>> R-sq:  within  = 0.1159                         Obs per
>>>
>>> group: min =         5
>>>>>
>>>>> between = 0.5186
>>>
>>> avg =       5.0
>>>>>
>>>>> overall = 0.4593
>>>
>>> max =         5
>>>>>
>>>>> Random effects u_i ~ Gaussian                   Wald
>>>
>>> chi2(2)       =    297.79
>>>>>
>>>>> corr(u_i, X)       = 0 (assumed)                Prob>
>>>
>>> chi2        =    0.0000
>>>>>
>>>>> priceclose       Coef.   Std. Err.      z    P>z     [95%
>>>
>>> Conf. Interval]
>>>>>
>>>>> eps    1.113035   .2084971     5.34   0.000     .7043883
>>>
>>>  1.521682
>>>>>
>>>>> bookvalue    1.394302   .1196459    11.65   0.000
>>>
>>> 1.159801    1.628804
>>>>>
>>>>> _cons    .5629992   .2070207     2.72   0.007     .1572462
>>>
>>>    .9687522
>>>>>
>>>>> sigma_u   2.1242726
>>>>> sigma_e   1.5953308
>>>>> rho   .63938518   (fraction of variance due to u_i)
>>>>>
>>>>>
>>>>> .
>>>>> . estimates store re
>>>>>
>>>>> .
>>>>> . hausman fe re
>>>>>
>>>>> ---- Coefficients ----
>>>>> (b)          (B)            (b-B)     sqrt(diag(V_b-V_B))
>>>>> fe           re         Difference          S.E.
>>>>>
>>>>> eps     .7770481     1.113035       -.3359869               .
>>>>> bookvalue     .8653121     1.394302       -.5289903         .102786
>>>>>
>>>>> b = consistent under Ho and Ha; obtained from xtreg B =
>>>
>>> inconsistent
>>>>>
>>>>> under Ha, efficient under Ho; obtained from xtreg
>>>>>
>>>>> Test:  Ho:  difference in coefficients not systematic
>>>>>
>>>>> chi2(2) = (b-B)'[(V_b-V_B)^(-1)](b-B)
>>>>> =   -15.59    chi2<0 ==>   model fitted on these
>>>>> data fails to meet the asymptotic
>>>>> assumptions of the Hausman test;
>>>>> see suest for a generalized test
>>>>>
>>>>>
>>>>> --
>>>>> Muhammad Anees
>>>>> MSc in Economics
>>>>> The University of Sheffield
>>>>> United Kingdom
>>>>> *
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>>>>
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-- 
Muhammad Anees
MSc in Economics
The University of Sheffield
United Kingdom

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