[R] 'plm' package problem

[londonphd]

Hi,

I ran 3 plm regressions (fixed effects) : twoways, individual and time
effects are added. I noticed that I am getting the same results in each
model. I expect the results to be different given the varying effects
introduced in each model. 

Can you please help sort this out, please? or Am I running the models
incorrectly?
Thanks
london

see the code and output below:

*> p1=plm(rgdppctg~log(rgdppct0)+log(s)+inv+govcons+Mortality+Oil,
data=pdata, model="within", effects="twoways")
> summary(p1)*

Oneway (individual) effect Within Model

Call:
plm(formula = rgdppctg ~ log(rgdppct0) + log(s) + in + govcons + Mortality +
Oil, data = pdata, model = "within",  
    effects = "/twoways/")

Balanced Panel: n=61, T=6, N=366

Residuals :
     Min.   1st Qu.    Median   3rd Qu.      Max. 
-0.190000 -0.014400 -0.000849  0.013900  0.162000 

Coefficients :
                  Estimate  Std. Error t-value  Pr(>|t|)    
log(rgdppct0)  -6.7528e-02  9.1153e-03 -7.4082 1.317e-12 ***
log(s)                   2.3820e-02  4.9427e-03  4.8193 2.295e-06 ***
in                         1.4166e-01  3.2254e-02  4.3921 1.560e-05 ***
govcons            -1.1618e-01  6.9840e-02 -1.6635   0.09726 .  
Mortality          -1.7923e+00  1.0105e+00 -1.7736   0.07714 .  
Oil                        4.9927e-05  3.8419e-05  1.2995   0.19476    
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Total Sum of Squares:    0.41398
Residual Sum of Squares: 0.30593
R-Squared      :  0.261 
      Adj. R-Squared :  0.21322 
F-statistic: 17.5998 on 6 and 299 DF, p-value: < 2.22e-16

####################################################################################
*> p1=plm(rgdppctg ~ log(rgdppct0) + log(s) + in + govcons + Mortality +
Oil, data = pdata, model = "within", effects="individual")
> summary(p1)*

Oneway (individual) effect Within Model

Call:
plm(formula = rgdppctg ~ log(rgdppct0) + log(s) + in + govcons + Mortality +
Oil, data = pdata, model = "within",  
    effects = "/individual/")

Balanced Panel: n=61, T=6, N=366

Residuals :
     Min.   1st Qu.    Median   3rd Qu.      Max. 
-0.190000 -0.014400 -0.000849  0.013900  0.162000 

Coefficients :
                  Estimate  Std. Error t-value  Pr(>|t|)    
log(rgdppct0)    -6.7528e-02  9.1153e-03 -7.4082 1.317e-12 ***
log(schooling)    2.3820e-02  4.9427e-03  4.8193 2.295e-06 ***
investments      1.4166e-01  3.2254e-02  4.3921 1.560e-05 ***
govcons               -1.1618e-01  6.9840e-02 -1.6635   0.09726 .  
Mortality             -1.7923e+00  1.0105e+00 -1.7736   0.07714 .  
OilCons                 4.9927e-05  3.8419e-05  1.2995   0.19476    
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Total Sum of Squares:    0.41398
Residual Sum of Squares: 0.30593
R-Squared      :  0.261 
      Adj. R-Squared :  0.21322 
F-statistic: 17.5998 on 6 and 299 DF, p-value: < 2.22e-16

####################################################################################

*> p1=plm(rgdppctg ~ log(rgdppct0) + log(s) + in + govcons + Mortality +
Oil, data = pdata, model = "within",  effects="/time/")
> summary(p1)*

Oneway (individual) effect Within Model

Call:
plm(formula = rgdppctg ~ log(rgdppct0) + log(s) + in + govcons + Mortality +
Oil, data = pdata, model = "within",  
    effects = "time")

Balanced Panel: n=61, T=6, N=366

Residuals :
     Min.   1st Qu.    Median   3rd Qu.      Max. 
-0.190000 -0.014400 -0.000849  0.013900  0.162000 

Coefficients :
                  Estimate  Std. Error t-value  Pr(>|t|)    
log(rgdppct0)          -6.7528e-02  9.1153e-03 -7.4082 1.317e-12 ***
log(s)                            2.3820e-02  4.9427e-03  4.8193 2.295e-06
***
in                                 1.4166e-01  3.2254e-02  4.3921 1.560e-05
***
govcons                    -1.1618e-01  6.9840e-02 -1.6635   0.09726 .  
Mortality                  -1.7923e+00  1.0105e+00 -1.7736   0.07714 .  
Oil                                4.9927e-05  3.8419e-05  1.2995   0.19476    
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Total Sum of Squares:    0.41398
Residual Sum of Squares: 0.30593
R-Squared      :  0.261 
      Adj. R-Squared :  0.21322 
F-statistic: 17.5998 on 6 and 299 DF, p-value: < 2.22e-16




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